Professor of Anesthesiology, Perioperative and Pain Medicine (Adult MSD) at the Stanford University Medical Center

Bio

Bio

Dr. Carvalho is the Chief of Obstetric Anesthesia and Professor in the Department of Anesthesiology, Stanford University Medical Center, and the President of the Society of Obstetric Anesthesia and Perinatology (SOAP). He has published extensively in the field of Obstetric Anesthesia with over 200 peer-reviewed articles, editorials, reviews, book chapters, and commentaries. He has received several NIH, pharmaceutical and institutional grants, and won numerous research awards including three Best Research Papers at SOAP scientific meetings. Dr. Carvalho has won the Teacher of the Year award at SOAP and at Stanford University?s Departments of Anesthesia. He has presented at over 150 regional, national, and international meetings and visiting professorships. His scholarly activities are focused on clinical and translational research in the field of cesarean and labor analgesia, perinatal pharmacology and immunology.

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Research & Scholarship

Current Research and Scholarly Interests

I have completed research in a number of important areas in obstetric anesthesia including: optimizing neuraxial techniques for labor and cesarean analgesia; predicting individual labor and cesarean pain and analgesic needs; evaluating pregnancy-induced and hormonal changes in pain perception; determining the role of cytokines and other biochemical mediators in incisional wounds; evaluating local anesthetic potency and anesthetic requirements during labor and cesarean delivery; determining epidural and spinal opioid applications and the role of long-acting neuraxial opioids in obstetric pain management; investigating peripartum hemostatic and coagulation changes; conducting cost-analyses of various obstetric anesthesia practices; optimizing the management of maternal cardiac arrest and other obstetrical emergencies; determining patient attitudes and ethnic preferences towards obstetric analgesia; determining the efficacy of peripheral wound drug administration; and pharmacokinetics/pharmacodynamics of drugs administered to pregnant women. My current area of research focus is in developing novel ways of improving post-cesarean and peripartum labor pain management, and developing detailed pharmacokinetics/pharmacodynamics models of key antenatal medications.

Clinical Trials

Calcium Chloride for Prevention of Uterine Atony During CesareanRecruiting

In this pilot study, investigators will administer calcium chloride or placebo to pregnant
women undergoing Cesarean delivery who have been identified as high risk for hemorrhage due
to poor uterine muscle contraction, or atony. They will assess whether a single dose of
calcium given immediately after the delivery of the fetus decreases the incidence of uterine
atony and bleeding for the mother. The pharmacokinetics of calcium chloride in pregnant women
will also be established. Data from this pilot study of 40 patients will be used to determine
sample size and appropriateness of a larger randomized clinical trial.

This study will attempt to objectively measure pain with an experimental device. The
investigators will apply the device to measure patients "pain" due to uterine contractions
during routine clinical care to correlate patients verbal pain ratings and analgesia
requirements to that measured by the device.

Stanford is currently not accepting patients for this trial.For more information, please contact Brendan Carvalho, MBBCh, FRCA, (650) 861-8607.

The ability to predict pain and then apply modified treatment protocols has been limited.
Current practice is for physicians to select standard post-operative pain treatment protocols
without patient consultation. This study hopes to determine if patient's involvement in
analgesic drug/dosage selection can optimize pain relief while minimizing related side
effects. This could result in a more patient-centered care model and individualized
perioperative analgesic treatment protocols based on patient's preferences, needs and
expectations.

Stanford is currently not accepting patients for this trial.For more information, please contact Brendan Carvalho, MBBCh, MDCH, (650) 724-2614.

This study proposes to compare the metabolism of Ampicillin and Gentamicin by pregnant women
to that of non-pregnant women; the placental transfer over time; and the subsequent
metabolism of the transferred drug(s) in the neonate.

Stanford is currently not accepting patients for this trial.For more information, please contact Brendan Carvalho, MBBCh, 650-861-8607.

Publications

All Publications

Abstract

PURPOSE OF REVIEW: The aim of this article is to describe enhanced recovery after surgery (ERAS) and its application to cesarean delivery.RECENT FINDINGS: ERAS is a standardized, multidisciplinary approach to improving the care of surgical patients, from the preoperative planning through the surgery and postoperative period. ERAS is associated with many benefits, including improved patient outcomes and satisfaction as well as reduced length-of-stay and cost. Obstetric implementation of ERAS protocols has lagged compared to other surgical subspecialties. Given the volume of cesarean deliveries worldwide, improving the quality and cost of care through broad application of ERAS could have significant benefits.SUMMARY: ERAS pathways specific to cesarean delivery should be implemented and can improve the quality of care provided.

Abstract

This systematic review aimed to determine whether enhanced recovery after caesarean delivery (ERAC) protocols should be adopted.We searched four databases and abstracts from meetings for studies comparing ERAC to standard care. We report interventions, outcomes, qualitative impact of ERAC implementation and use GRADE scoring to determine quality of evidence and make recommendations regarding ERAC adoption, based on key outcomes (length of stay, financial savings, satisfaction, re-admission, opioid usage, breastfeeding success and maternal-neonatal bonding).Eleven published studies and 36 abstracts evaluating ERAC were included. Forty-two study interventions (40 in published studies) and 90 outcome measures (60 in published studies) were used. Most studies showed a reduction in hospital stay (6/7 studies) and reduced costs (2/2 studies) with ERAC compared with standard care. Satisfaction was inconsistently reported. Re-admission rates were similar between groups. Two studies showed a reduction and two showed no difference in opioid consumption with ERAC. One study showed improvement and another showed no change in outpatient breastfeeding rates with ERAC. One study showed better inpatient maternal-neonatal bonding. The GRADE level of evidence was low or very low for all outcomes.Studies evaluating ERAC used heterogeneous interventions and outcomes. Although there is currently low- or very low-level evidence supporting all outcomes evaluated, the majority of studies showed some benefits and none reported harm. On balance, we recommend the use of ERAC. Future studies are needed to strengthen ERAC recommendations by standardising interventions and reported outcomes.

Abstract

Neuraxial analgesia provides excellent pain relief in labor. Optimizing initiation and maintenance of neuraxial labor analgesia requires different strategies. Combined spinal-epidurals or dural puncture epidurals may offer advantages over traditional epidurals. Ultrasound is useful in certain patients. Maintenance of analgesia is best achieved with a background regimen (either programmed intermittent boluses or a continuous epidural infusion) supplemented with patient-controlled epidural analgesia and using dilute local anesthetics combined with opioids such as fentanyl. Nitrous oxide and systemic opioids are also used for pain relief. Nitrous oxide may improve satisfaction despite variable effects on pain. Systemic opioids can be administered by healthcare providers or using patient-controlled analgesia. Appropriate choice of drug should take into account the stage and progression of labor, local safety protocols, and maternal and fetal/neonatal side effects. Pain in labor is complex, and women should fully participate in the decision-making process before any one modality is selected.

Abstract

BACKGROUND: The impact of the electronic medical record (EMR) on nursing workload is not well understood. The objective of this descriptive study was to measure the actual and perceived time that nurses spend on the EMR in the operating room during cesarean births.METHODS: Twenty scheduled cesarean births were observed. An observer timed the circulating nurse's EMR use during each case. Immediately after each case, the nurse completed a questionnaire to estimate EMR time allocation during the case and their desired time allocation for a typical case. They were also asked about time allotted to various activities preoperatively, intraoperatively, and postoperatively for a typical cesarean birth.RESULTS: Mean observed nurse EMR time was 36 ± 12 minutes per case, 40% ± 10% of the duration of the cesarean delivery. Nurses tended to estimate greater time spent on the EMR; the perceived mean proportion of time spent on the EMR (55%) was greater than the actual timed value of 40% (P = 0.020). Nurse's desired amount of time spent on the EMR was 22% ± 15% of the case duration, significantly less than actual time spent on the EMR (P = 0.007).CONCLUSIONS: On average, nurses spent 40% of their intraoperative time on the EMR during cesarean births, and this time burden was distributed across the perioperative period. These findings highlight the time burden of EMRs and suggest that EMR functionality should be better aligned with end-user needs. Future studies are needed to better understand the impacts of intraoperative EMR use on patient safety and patient/nursing/clinician communication.

Abstract

BACKGROUND: Despite significant improvements in outcomes following non-obstetric surgery with implementation of enhanced recovery after surgery (ERAS) protocols, development of these protocols for cesarean delivery is lacking. We evaluated implementation of an ERAS protocol for patients undergoing elective cesarean delivery, specifically the effect on opioid consumption, pain scores and length of stay as well as complications and re-admissions.METHODS: An ERAS protocol was developed and implemented for women undergoing elective cesarean delivery. The protocol construction included specific evidence-based items applicable to peripartum management and these were grouped into the three major phases of patient care: antepartum, intrapartum and postpartum. A before-and-after study design was used to compare maternal outcomes. To account for confounders between groups, a propensity matched scoring analysis was used. The primary outcome was postpartum opioid use in mg-morphine equivalents (MMEQ).RESULTS: We included 357 (n=196 before; n=161 after) women who underwent elective cesarean delivery. A significant difference in opioid consumption (28.4?±?24.1 vs 46.1?±?37.0 MMEQ, P?<0.001) and in per-day postoperative opioid consumption (10.9?±?8.7 vs 15.1?±?10.3 MMEQ, P?<0.001), lower peak pain scores (7 [5-9] vs 8 [7-9], P=0.007) and a shorter hospital length of stay (2.5?±?0.5 vs 2.9?±?1.2?days, P?<0.001) were found after the introduction of the ERAS protocol.CONCLUSIONS: Implementation of ERAS protocols for elective cesarean delivery is associated with significant improvements in analgesic and recovery outcomes. These improvements in quality of care suggest ERAS protocols should be considered for elective cesarean delivery.

Abstract

We performed a systematic review using 'consensus-based standards for the selection of health measurement instruments' (COSMIN) criteria to identify and evaluate the quality of patient-reported outcome measures (PROM) instruments that have been utilised to assess functional recovery following caesarean section, and determine the optimal instrument for use in this setting. A literature search was performed using five databases. Studies were included if a psychometrically validated instrument was used to assess functional recovery following caesarean section. The COSMIN appraisal checklist was utilised to: assess the quality of included studies reporting PROMs; determine psychometric quality of instruments; and identify the most promising instruments for use after caesarean section. We identified 13 PROMs used to assess the quality of recovery after caesarean section in 20 studies that included 9214 patients. All PROMs contained between two and seven domains. Five out of the 13 PROMs were specific to postpartum recovery. Only two of these PROM instruments were specifically designed for use after caesarean section (Obstetric Quality of Recovery-11 and Recovery from Caesarean SectionScale). We found very few adequate measures of functional recovery following caesarean section. Overall, the Obstetric Quality of Recovery-11 achieved the highest COSMIN standards for any PROM. Future development of PROMs for use after caesarean section should include multiple domains, and undergo validation as outlined by the COSMIN criteria.

Abstract

It is routine to give a uterotonic drug following delivery of the neonate during caesarean section. However, there is much heterogeneity in the relevant research, which has largely been performed in low-risk elective cases or women with uncomplicated labour. This is reflected in considerable variation in clinical practice. There are significant differences between dose requirements during elective and intrapartum caesarean section. Standard recommended doses are higher than required, with the potential for acute cardiovascular adverse effects. We recommend a small initial bolus dose of oxytocin, followed by a titrated infusion. The recommended doses of oxytocin may have to be increased in women with risk factors for uterine atony. Carbetocin at equipotent doses to oxytocin has similar actions, while avoiding the requirement for a continuous infusion after the initial dose and reducing the need for additional uterotonics. As with oxytocin, carbetocin dose requirements are higher for intrapartum caesarean sections. A second-line agent should be considered early if oxytocin/carbetocin fails to produce good uterine tone. Women with cardiac disease may be very sensitive to the adverse effects of oxytocin and other uterotonics, and their management needs to be individualised.

Abstract

Patient-centred care and factors associated with patient satisfaction with anaesthesia have been widely studied. However, the most important considerations in the setting of obstetric anaesthesia are uncertain. Identification of, and addressing, factors that contribute to patient dissatisfaction may improve quality of care. We sought to identify factors associated with<100% satisfaction with obstetric anaesthesia care. At total of 4297 women treated by anaesthetists provided satisfaction data 24h after vaginal and 48h after caesarean delivery. As 78% of women were 100% satisfied, we studied factors associated with the dichotomous variable, 100% satisfied vs. < 100% satisfied. We evaluated patient characteristics and peripartum factors using multivariable sequential logistic regression. The following factors were strongly associated with maternal dissatisfaction after vaginal delivery: pain intensity during the first stage of labour; pain intensity during the second stage of labour; postpartum pain intensity; delay >15min in providing epidural analgesia and postpartum headache (all p<0.0001). Pruritus (p=0.005) also contributed to dissatisfaction after vaginal delivery, whereas non-Hispanic ethnicity was negatively associated with dissatisfaction (p=0.01). After caesarean delivery, the intensity of postpartum pain (p<0.0001), headache (p=0.001) and pruritus (p=0.001) were linked to dissatisfaction. Hispanic ethnicity also had a negative relationship with dissatisfaction after caesarean delivery (p=0.005). Thus, inadequate or delayed analgesia and treatment-related side-effects are associated with maternal dissatisfaction with obstetric anaesthesia care. Development of protocols to facilitate identification of ineffective analgesia and provide an appropriate balance between efficacy and side-effects, are important goals to optimise maternal satisfaction.

Abstract

BACKGROUND: Dexamethasone is an effective analgesic and anti-emetic in patients undergoing many surgical procedures but its effects on pain after cesarean delivery are poorly studied. The aim of this study was to evaluate if routine intra-operative administration of dexamethasone improved analgesia and decreased postoperative nausea and vomiting after scheduled cesarean delivery.METHODS: Electronic medical record data for scheduled cesarean deliveries performed under neuraxial anesthesia, before and after a practice change that introduced the routine use of intravenous dexamethasone 4?mg, were obtained. Patients were analyzed based on whether they received routine care (n=182) or also received dexamethasone (n=187). The primary outcome was time to first opioid use. Secondary outcomes included postoperative opioid consumption, pain scores, incidence and treatment of postoperative nausea and vomiting, satisfaction and length of stay.RESULTS: There was no significant difference between groups in median time to first postoperative opioid administration (15.8 [3.4-48.0] h routine care vs 14.7 [3.2-38.8] h routine care plus dexamethasone, P=0.08). There were no significant differences in any secondary outcomes.CONCLUSIONS: This impact study involving more than 360 patients suggests that routine administration of intra-operative intravenous dexamethasone 4?mg does not provide additional analgesic benefit after scheduled cesarean delivery, in the context of a multimodal postoperative analgesic regimen. Studies are required to determine if a larger dose or repeated administration influence postoperative analgesia or side effects, or whether certain subsets of patients may benefit.

Abstract

Abdominal wall blocks rely on the spread of local anesthetic within musculofascial planes to anesthetize multiple small nerves or plexuses, rather than targeting specific nerve structures. Ultrasonography is primarily responsible for the widespread adoption of techniques including transversus abdominis plane and rectus sheath blocks, as well as the introduction of novel techniques such as quadratus lumborum and transversalis fascia blocks. These blocks are technically straightforward and relatively safe and reduce pain and opioid requirements in many clinical settings. The data supporting these outcomes, however, can be inconsistent because of heterogeneity of study design. The extent of sensory blockade is also somewhat variable, because it depends on the achieved spread of local anesthetic and the anatomical course of the nerves being targeted. The blocks mainly provide somatic analgesia and are best used as part of a multimodal analgesic regimen. This review summarizes the anatomical, sonographic, and technical aspects of the abdominal wall blocks in current use, examining the current evidence for the efficacy and safety of each.

Abstract

The majority of women undergoing cesarean delivery in the United States receive neuraxial morphine, the most effective form of postoperative analgesia for this surgery. Current American Society of Anesthesiologists (ASA) and American Society of Regional Anesthesia and Pain Medicine (ASRA) recommend respiratory monitoring standards following neuraxial morphine administration in the general surgical population that may be too frequent and intensive when applied to the healthy obstetric population receiving a single dose of neuraxial morphine at the time of surgery. There is limited evidence to support or guide the optimal modality, frequency, and duration of respiratory monitoring in the postoperative cesarean delivery patient receiving a single dose of neuraxial morphine. Consistent with the mission of the Society for Obstetric Anesthesia and Perinatology (SOAP) to improve outcomes in pregnancy for women and neonates, the purpose of this consensus statement is to encourage the use of this highly effective analgesic technique while promoting safe practice and patient-centered care. The document aims to reduce unnecessary interruptions from respiratory monitoring in healthy mothers while focusing vigilance on monitoring in those women at highest risk for respiratory depression following neuraxial morphine administration. This consensus statement promotes the use of low-dose neuraxial morphine and multimodal analgesia after cesarean delivery, gives perspective on the safety of this analgesic technique in healthy women, and promotes patient risk stratification and perioperative risk assessment to determine and adjust the intensity, frequency, and duration of respiratory monitoring.

Abstract

Current pain and analgesic management strategies apply a standardized one-size-fits-all approach to all women undergoing cesarean delivery. These standardized protocols do not account for significant variability in women's pain and may lead to under-treatment in patients with high analgesic needs and overtreatment, associated with increased analgesic-related side effects, in women with low analgesic needs and higher analgesic drug sensitivity. Pre-operative identification of patients at risk of developing severe pain might allow clinicians to optimize care by offering personalized, stratified or targeted analgesic treatment protocols. Pre-operative pain prediction tools are only of moderate value in this regard. Pain reporting during local anesthetic infiltration and answering simple rating questions about anticipated pain and analgesic needs are the easiest tools to apply and show some promise for post cesarean delivery pain prediction. Patient-driven analgesic dose and protocol selection (based on individual preferences for pain relief and for avoidance of side effects after cesarean delivery) may optimally balance individual pain needs and side effect concerns compared to standardized postoperative pain treatment protocols. Individualized or stratified post-discharge opioid prescribing practices have been shown to reduce unnecessary opioid analgesic prescriptions and consumption, so should be implemented routinely. Outcomes other than pain and analgesic use, including recovery measures and maternal satisfaction metrics, should be considered when evaluating personalized or patient-selected pain treatment protocols.

Abstract

BACKGROUND: Choice of postcesarean delivery analgesic protocol may improve pain experience and reduce analgesic requirements.METHODS: Cesarean delivery patients were randomly assigned either to choose their postcesarean delivery analgesia protocol or to have no choice and receive routine care. Choices were low (50 mug intrathecal morphine), medium (identical to routine care: 150 mug intrathecal morphine), or high (300 mug intrathecal morphine with 600mg oral gabapentin). All groups received scheduled acetaminophen and ibuprofen. The primary outcome was oxycodone requirements 0-48hours postdelivery in those offered versus not offered a choice.RESULTS: Of 160 women enrolled, 120 were offered a choice and 40 were not offered a choice. There was no difference in oxycodone requirements or pain associated with choice, but those who had a choice expressed more satisfaction than those who did not have a choice (mean (95%CI) difference 5% (0% to 10 %), p=0.005). In the choice group, the high dose group required more oxycodone (5 (0 to 15)mg 0-24hours after delivery and 15 (10 to 25) mg at 24-48hours; p=0.05 and p=0.001) versus the low and medium groups. The low dose group had less pruritus (p=0.001), while the high dose group had more vomiting (p=0.01) requiring antiemetic treatment (p=0.04).CONCLUSION: Having a choice compared with no choice routine care did not reduce oxycodone requirements or pain scores. However, women have insight into their analgesic needs; women offered a choice and who chose the higher dose analgesic protocol required more oxycodone, and women who chose the lower dose protocol required less oxycodone. Despite providing additional analgesic (six times more intrathecal morphine plus gabapentin in high dose vs low dose protocols), we still did not equalize postcesarean oxycodone requirement differences between groups.TRIAL REGISTRATION NUMBER: NCT02605187.

Abstract

We describe the management of a pregnant patient with osteogenesis imperfecta with a history of numerous fractures, severe scoliosis, and anticipated difficult airway. Her pregnancy was complicated by progressive shortness of breath and a fetal diagnosis of osteogenesis imperfecta. Spine anatomy precluded neuraxial anesthesia. Cesarean delivery was performed under general anesthesia at 34 weeks. Immediately after awake fiberoptic intubation and induction of general anesthesia, capnography waveform was lost with rapid profound oxygen desaturation. A supraglottic airway device was placed, oxygenation maintained with supraglottic airway and positive pressure ventilation throughout case, and the baby was delivered with Apgars of 8 and 9.

Abstract

BACKGROUND: The study aimed to compare the accuracy of epidural depth estimation of a handheld ultrasound device, with an integrated algorithm that estimates epidural depth (AU; Accuro, Rivanna Medical), to that of a console ultrasound machine (GU; GE LOGICTM S8).METHODS: Women requesting labor epidural analgesia consented to this prospective cohort study. The L2/3, L3/4, and L4/5 interspaces and the respective depths to the epidural space were identified, marked and measured using an AU and GU. An anesthesia provider who was blinded to ultrasound depth measurements performed epidural analgesia at one of the ultrasound identified insertion points, and recorded the Tuohy needle depth at loss-of-resistance. Bland Altman analysis was used to measure the agreement between the epidural depths measured by the AU and GU.RESULTS: A total of 47 women were analyzed. The mean?±?standard deviation body mass index of the study cohort was 29?±?5?kg/m2 [range 23-45]. The mean difference between the epidural depths measured by the AU and GU was -0.29?cm [95% limit of agreement 0.50 to -0.91]. The mean difference between the depth to the epidural space measured by the GU versus the needle depth was -0.33?cm [95% CI -0.49 to -0.16]. The previously reported AU versus needle depth was -0.61?cm [95% CI -0.79 to -0.44].CONCLUSION: The AU and GU provided comparable epidural depth estimates. The AU device may be a reasonable alternative to more sophisticated ultrasound devices in determining the epidural space and depth in a non-obese obstetric population.

Abstract

Preeclampsia is one of the most severe pregnancy complications and a leading cause of maternal death. However, early diagnosis of preeclampsia remains a clinical challenge. Alterations in the normal immune adaptations necessary for the maintenance of a healthy pregnancy are central features of preeclampsia. However, prior analyses primarily focused on the static assessment of select immune cell subsets have provided limited information for the prediction of preeclampsia. Here, we used a high-dimensional mass cytometry immunoassay to characterize the dynamic changes of over 370 immune cell features (including cell distribution and functional responses) in maternal blood during healthy and preeclamptic pregnancies. We found a set of eight cell-specific immune features that accurately identified patients well before the clinical diagnosis of preeclampsia (median area under the curve (AUC) 0.91, interquartile range [0.82-0.92]). Several features recapitulated previously known immune dysfunctions in preeclampsia, such as elevated pro-inflammatory innate immune responses early in pregnancy and impaired regulatory T (Treg) cell signaling. The analysis revealed additional novel immune responses that were strongly associated with, and preceded the onset of preeclampsia, notably abnormal STAT5ab signaling dynamics in CD4+T cell subsets (AUC 0.92, p = 8.0E-5). These results provide a global readout of the dynamics of the maternal immune system early in pregnancy and lay the groundwork for identifying clinically-relevant immune dysfunctions for the prediction and prevention of preeclampsia.

Abstract

Prolonged preoperative fasting may lead to dehydration, hypoglycaemia, ketoacidosis and delayed recovery. We hypothesised that a patient educational initiative would decrease our preoperative fasting periods for elective caesarean delivery.This was an observational quality improvement impact study. Elective caesarean patients who delivered during our study period were included in the study, 40 patients in the pre-intervention and 40 patients in the post-intervention groups. Only English-speaking patients were included. We developed a patient educational pamphlet outlining preoperative fasting and analgesic expectations for caesarean delivery that was given to every patient at her preoperative anaesthesia consultation. The pamphlet included the American Society of Anesthesiologists' preoperative fasting and enhanced recovery carbohydrate drink recommendations. The primary outcome measure was intended fasting duration for liquids (defined as time from last reported liquid consumption to scheduled caesarean delivery) before and after the patient educational initiative. Secondary outcomes included solid fasting time, types of liquids and solids consumed.The intended median (interquartile range) fasting time for liquids decreased from 10 (8.9-12) h to 3.5 (2.5-10) h (p<0.001). The fasting period for solids was not significantly different: 12.5 (10.5-14) h pre- versus 12.4 (10.6-14) h post-pamphlet introduction (p=0.384). Despite the recommendation, only 22.5% consumed a carbohydrate-containing drink with a modest decrease in water consumption (87.5% before and 67.5% after; p=0.009).A patient educational pamphlet significantly reduced fasting time for clear liquids. Future studies are needed to determine what barriers limited adherence to the recommended carbohydrate-containing drink consumption.

Abstract

To evaluate whether an order set change that halved the initial dose of oxycodone and allowed the remainder to be given 1 hour later, if requested, was associated with reduced opioid use and side effects after cesarean delivery.This retrospective, clinical practice study reviewed electronic medical records after implementation of a new order set for cesarean delivery. Oxycodone orders changed from 5 mg (for verbal pain score of 4/10 or lower) and 10 mg (for 5-10/10) to 2.5 mg (for verbal pain score 1-4/10) or 5 mg (for 5-10/10), and the patient requesting pain relief, with a nurse check within 1 hour to administer another 2.5 or 5 mg, respectively, if needed. The primary outcome was opioid use (in intravenous morphine equivalents) in the first 48 hours. Secondary outcomes included incidence and treatment of nausea or vomiting and pruritis, average and peak verbal pain scores within 48 hours, and satisfaction.The records of 1,050 women were examined (542 before and 508 after the change). Opioid use in the first 48 hours was lower after the practice change (median [interquartile range] 10.0 [1.3-25.0] mg before vs 4.4 [0-12.5] mg after; P

Abstract

If conversion of labor epidural analgesia to cesarean delivery anesthesia fails, the anesthesiologist can be confronted with a challenging clinical dilemma. Optimal management of a failed epidural top up continues to be debated in the absence of best practice guidelines.All members of the Obstetric Anaesthetists' Association in the United Kingdom were emailed an online survey in May 2017. It obtained information on factors influencing the decision to utilize an existing labor epidural for cesarean section and, if epidural top up resulted in no objective sensory block, bilateral T10 sensory block, or unilateral T6 sensory block, factors influencing the management and selection of anesthetic technique. Differences in management options between respondents were compared using the chi-squared test.We received 710 survey questionnaires with an overall response rate of 41%. Most respondents (89%) would consider topping up an existing labor epidural for a category-one cesarean section. In evaluating whether or not to top up an existing labor epidural, the factors influencing decision-making were how effective the epidural had been for labor pain (99%), category of cesarean section (73%), and dermatomal level of blockade (61%). In the setting of a failed epidural top up, the most influential factors determining further anesthetic management were the category of cesarean section (92%), dermatomal level of blockade (78%), and the assessment of maternal airway. Spinal anesthesia was commonly preferred if an epidural top up resulted in no objective sensory block (74%), bilateral T10 sensory block (57%), or unilateral T6 sensory block (45%). If the sensory block level was higher or unilateral, then a lower dose of intrathecal local anesthetic was selected and alternative options such as combined-spinal epidural and general anesthesia were increasingly favored.Our survey revealed variations in the clinical management of a failed epidural top up for cesarean delivery, suggesting guidelines to aid decision-making are needed.

Abstract

Magnesium sulfate is the anticonvulsant of choice for eclampsia prophylaxis and treatment; however, the recommended dosing regimens are costly and cumbersome and can be administered only by skilled health professionals. The objectives of this study were to develop a robust exposure-response model for the relationship between serum magnesium exposure and eclampsia using data from large studies of women with preeclampsia who received magnesium sulfate, and to predict eclampsia probabilities for standard and alternative (shorter treatment duration and/or fewer intramuscular injections) regimens. Exposure-response modeling and simulation were applied to existing data. A total of 10 280 women with preeclampsia who received magnesium sulfate or placebo were evaluated. An existing population pharmacokinetic model was used to estimate individual serum magnesium exposure. Logistic regression was applied to quantify the serum magnesium area under the curve-eclampsia rate relationship. Our exposure-response model-estimated eclampsia rates were comparable to observed rates. Several alternative regimens predicted magnesium peak concentration

Abstract

During cesarean hysterectomy for a placenta accreta, a 36-year-old parturient underwent a massive resuscitation for profound bleeding and also suffered a pulmonary embolus leading to cardiac arrest. Chest compressions and epinephrine were required for resucitation. When surgery was complete, she was taken to the intensive care unit on an epinephrine infusion and inhaled nitric oxide but was brought back to the operating room after 3 h for surgical exploration. Echocardiography revealed a poorly contracting left ventricle, and an intra-aortic balloon pump was inserted. She gradually recovered full function and was discharged home after 35 days.

Abstract

Colloid preloading diminishes post-spinal hypotension. However, whether colloid preloading is superior to crystalloid co-loading is uncertain. In this retrospective study, we compared the effects of a colloid preload versus a crystalloid co-load on vasopressor requirements and maternal haemodynamics among women undergoing elective caesarean delivery (CD) with spinal anaesthesia.We extracted data from the medical records of 160 healthy women who underwent elective CD with spinal anaesthesia at an academic obstetric centre before and after an institutional fluid-loading protocol change. Patients received a 500 mL 6% hydroxyethyl starch preload or a 1000 mL crystalloid co-load. The primary outcome was the total phenylephrine dose administered from spinal block placement to delivery.Our cohort comprised 79 women in the colloid group and 77 women in the crystalloid group. The mean phenylephrine use was significantly lower in the colloid group than in the crystalloid group (489±403 ?g vs. 647±464 ?g, respectively, p=0.02). The maximal drop in systolic blood pressure was greater in the colloid group than in the crystalloid group (36±20 mmHg vs. 29±16 mmHg, respectively, p=0.02). There were no clinically significant differences between the groups in heart rate, blood loss, temperature and Apgar scores.Vasopressor use was lower in colloid preloading than in crystalloid co-loading. However, differences in all outcome measures were minimal and likely clinically insignificant, suggesting that both fluid-loading techniques are appropriate to use for the prevention of spinal hypotension in women undergoing CD.

Abstract

The prevalence of neuraxial opioid-induced clinically significant respiratory depression (CSRD) after cesarean delivery is unknown. We sought to review reported cases of author-reported respiratory depression (ARD) to calculate CSRD prevalence. A 6-database literature search was performed to identify ARD secondary to neuraxial morphine or diamorphine, in parturients undergoing cesarean delivery. "Highest" (definite and probable/possible) and "lowest" (definite) prevalences of CSRD were calculated. Secondary outcomes included: (1) prevalence of CSRD associated with contemporary doses of neuraxial opioid, (2) prevalence of ARD as defined by each study's own criteria, (3) case reports of ARD, and (4) reports of ARD reported by the Anesthesia Closed Claims Project database between 1990 and 2016. We identified 78 articles with 18,455 parturients receiving neuraxial morphine or diamorphine for cesarean delivery. The highest and lowest prevalences of CSRD with all doses of neuraxial opioids were 8.67 per 10,000 (95% CI, 4.20-15.16) and 5.96 per 10,000 (95% CI, 2.23-11.28), respectively. The highest and lowest prevalences of CSRD with the use of clinically relevant doses of neuraxial morphine ranged between 1.63 per 10,000 (95% CI, 0.62-8.77) and 1.08 per 10,000 (95% CI, 0.24-7.22), respectively. The prevalence of ARD as defined by each individual paper was 61 per 10,000 (95% CI, 51-74). One published case report of ARD met our inclusion criteria, and there were no cases of ARD from the Closed Claims database analysis. These results indicate that the prevalence of CSRD due to neuraxial morphine or diamorphine in the obstetric population is low.

Abstract

Magnesium sulfate is the standard therapy for prevention and treatment of eclampsia. Twostandard dosing regimens require either continuous intravenous infusion or frequent, large-volume intramuscular injections, which may preclude patients from receiving optimal care. This project sought to identify alternative, potentially more convenient, but similarly effective dosing regimens that could be used in restrictive clinical settings. A 2-compartment population pharmacokinetic (PK) model was developed to characterize serial PK data from 92pregnant women with preeclampsia who received magnesium sulfate. Body weight and serum creatinine concentration had a significant impact on magnesium PK. The final PK model was used to simulate magnesium concentration profiles for the 2standard regimens and several simplified alternative dosing regimens. The simulations suggest that intravenous regimens with loading doses of 8 g over 60 minutes followed by 2 g/h for 10 hours and 12 g over 120 minutes followed by 2 g/h for 8 hours (same total dose as the standard intravenous regimen but shorter treatment duration) would result in magnesium concentrations below the toxic range. For the intramuscular regimens, higher maintenance doses given less frequently (4 g intravenously + 10-g intramuscular loading doses with maintenance doses of 8 g every 6hours or 10 g every 8 hours for 24 hours) or removal of the intravenous loading dose (eg, 10 g intramusculary every 8 hours for 24 hours) may be reasonable alternatives. In addition, individualized dose adjustments based on body weight and serum creatinine were proposed for the standard regimens.

Abstract

BACKGROUND: Visual estimation and gravimetric methods are commonly used to quantify the volume of blood loss during cesarean delivery (CD). However, the correlation between blood loss and post-CD hemoglobin (Hb) is poorly studied, and it is unclear whether the correlation varies according to how blood loss is measured.METHODS: After obtaining Institutional Review Board approval, we performed a prospective study of 61 women undergoing CD to assess the relations between post-CD Hb and blood loss measured using 4 modalities: gravimetric blood loss measurement (gBL), visual blood loss estimation by a blinded obstetrician (oBL) and anesthesiologist (aBL), and the Triton System (tBL). Hb was measured preoperatively and within 10 minutes after CD. gBL was quantified as blood volume in a suction canister in addition to the weight of blood-soaked sponges. tBL was measured with the Triton System by photographing blood-soaked sponges and suction canister contents. To assess the relation between blood loss and post-CD Hb, we performed correlation analyses and compared the magnitude of the correlations across the 4 measurement modalities using William t test. A Bonferroni correction was set to identify a statistically significant correlation (P < .0125) and statistically significant differences between correlation coefficients (P < .008).RESULTS: The mean (standard deviation) preoperative Hb was 12 (1.1) g/dL and post-CD Hb was 11.3 (1.0) g/dL. Median (interquartile range) values for gBL, oBL, aBL, and tBL were 672 mL (266-970), 700 mL (600-800), 750 mL (600-1000), and 496 mL (374-729), respectively. A statistically significant but weak correlation was observed between tBL and post-CD Hb (r = -0.33; P = .01). No statistically significant correlations were observed among aBL (r = -0.25; P = .06), oBL (r = -0.2; P = .13), and gBL (r = -0.3; P = .03) with post-CD Hb. We did not detect any significant differences between any 2 correlation coefficients across the 4 modalities.CONCLUSIONS: Given that we observed only weak correlations between each modality with post-CD Hb and no significant differences in the magnitude of the correlations across the 4 modalities, there may be limited clinical utility in estimating post-CD Hb from blood loss values measured with any of the 4 modalities.

Abstract

The optimal local-anaesthetic (LA) dose for transversus-abdominis-plane (TAP) block is unclear. In this meta-analysis, we aimed to determine whether TAP blocks for Caesarean delivery (CD) with low-dose (LD) LA demonstrated non-inferiority in terms of analgesic efficacy, compared with high-dose (HD) LA.A literature search was performed for randomised controlled trials examining the analgesic efficacy of TAP blocks vs control after CD. The different dosing used in these studies was classified as HD or LD (bupivacaine equivalents >50 or ?50 mg per block side, respectively). The pooled results of each dose group vs control were indirectly compared using the Q test. The primary outcome was 24 h opioid consumption. Secondary outcomes included 6 and 24 h postoperative pain scores, time to first analgesia, 6 h opioid consumption, opioid-related side-effects, and maternal satisfaction.Fourteen studies consisting of 770 women (389 TAP and 381 control) were included. Compared with controls, the 24 h opioid consumption (milligram morphine equivalents) was lower in HD [mean difference (MD) 95% confidence interval (CI) -22.41 (-38.56, -6.26); P=0.007; I2=93%] and LD [MD 95% CI -16.29 (-29.74, -2.84); P=0.02; I2=98%] TAP groups. However, no differences were demonstrated between the HD and LD groups (P=0.57). There were also no differences between the HD and LD groups for the 6 h opioid consumption, time to first analgesia, 6 and 24 h pain scores, postoperative nausea and vomiting, pruritus, and maternal satisfaction.Low-dose TAP blocks for Caesarean delivery provide analgesia and opioid-sparing effects comparable with the high-dose blocks. This suggests that lower doses can be used to reduce local anaesthetic toxicity risk without compromising the analgesic efficacy.

Abstract

The objective of this meta-analysis was to determine the efficacy of glycopyrrolate at reducing spinal hypotension during cesarean delivery.A literature search was performed to identify randomized controlled trials investigating the effect of glycopyrrolate on spinal-induced hypotension during cesarean delivery. Primary outcomes were intraoperative hypotension and vasopressor requirement (phenylephrine equivalents). Secondary outcomes included heart rate (HR), nausea and vomiting, dry mouth, and Apgar scores. Risk ratios (RRs), and mean differences (MDs) were calculated using random-effects modeling with 95% confidence intervals for primary outcomes and 99% confidence intervals for secondary outcomes.Five randomized controlled trials met our inclusion criteria. A total of 311 patients were included: 153 received glycopyrrolate and 158 placebo. The incidence of spinal-induced hypotension was no different with prophylactic glycopyrrolate compared to control (RR, 0.93 [0.71-1.21]; P = .59), but the total phenylephrine dose required was significantly reduced with glycopyrrolate (MD, -62.64 ?g [-107.61 to -17.66 ?g]; P = .006). The maximal HR achieved in the glycopyrrolate group was significantly higher compared to controls (MD, 15.85 bpm [5.40-26.31]; P < .0001); however, the incidence of bradycardia was not statistically different. The incidence of intraoperative nausea and vomiting was not different between groups; however, glycopyrrolate increased the risk of dry mouth (RR, 5.15 [1.82-14.57]; P < .0001). Apgar scores at 1 and 5 minutes did not differ between groups.Prophylactic glycopyrrolate does not reduce the incidence of spinal-induced hypotension but results in a modest reduction in vasopressor requirements while increasing maternal HR.

Abstract

Regional anesthesia is a rapidly growing subspecialty. There are few published meta-analyses exploring pain outcome measures utilised in regional anesthesia randomized controlled trials (RCTs), which may be due to heterogeneity in outcomes assessed. This systematic review explores postoperative pain outcomes utilised in regional anesthesia RCTs.A literature search was performed using three databases (Medline, Embase, and CINAHL). Regional anesthesia RCTs with postoperative pain as a primary outcome were included if written in English and published in one of the top 20 impact factor journals between 2005 and 2017. Study quality was assessed using the Cochrane Collaboration's tool for assessing risk of bias.From the 31 included articles, 15 different outcome measures in total were used to assess postoperative pain. The most commonly (16/31) used outcome measures were verbal numerical grading of pain out of 10, total opioid consumption, and visual analogue scale 10?cm (VAS). The need for analgesia was used as an outcome measure where studies did not use a pain rating score. Ten studies reported pain scores on activity and 27/31 studies utilised ?2 pain outcomes. Time of measurement of pain score also varied with a total of 51 different time points used in total.Analysis of the articles demonstrated heterogeneity and inconsistency in choice of pain outcome and time of measurement within regional anesthesia studies. Identification of these pain outcomes utilised can help to create a definitive list of core outcomes, which may guide future researchers when designing such studies.

Abstract

Labor epidural analgesia failure may relate to nonmidline placement of epidural catheters. We hypothesized that greater deviations of the epidural catheter insertion point from the ultrasound (US)-determined midline would be associated with less effective labor analgesia.A prospective ethically approved cohort study was conducted. Fifty-two healthy average-sized women receiving labor epidural analgesia, inserted by the landmark technique, were approached after delivery. Immediately after removing the epidural catheter, we determined the epidural space midline using US and compared it to the epidural catheter insertion point and to the patient-identified midline (assessed by a pinprick in 1-mm increments). Correlations between the US midline-to-catheter insertion point distance and additional epidural local anesthetic requirements (primary outcome), pain verbal numeric rating scale scores (0-10) 1 hour after epidural insertion, and maternal satisfaction with analgesia were determined. The differences in distances were assessed by a Bland-Altman analysis.There were no significant correlations between the US midline-to-epidural catheter insertion point distance and additional epidural local anesthetic requirements (R2 ?=?0.138; P?=?.33), pain verbal numeric rating scale scores 1 hour after the epidural (R2 ?=?0.121; P?=?.40) or maternal satisfaction (R2 ?=?0.085; P?=?.57). The Bland-Altman analysis revealed that the mean ± SD US midline-to-epidural catheter insertion point distance and patient-identified midline distances were 0.38?±?0.31 and 0.35?±?0.46?cm, respectively.In our laboring population, the hypothesis that nonmidline epidural insertion is associated with less-effective labor analgesia was not confirmed in this study cohort. We found minimal differences in distances between the US midline to epidural catheter insertion point and US midline to patient-identified midline.

Abstract

The Malignant Hyperthermia Association of the United States recommends that dantrolene be available for administration within 10 min. One approach to dantrolene availability is a malignant hyperthermia cart, stocked with dantrolene, other drugs, and supplies. However, this may not be of cost benefit for maternity units, where triggering agents are rarely used.The authors performed a cost-benefit analysis of maintaining a malignant hyperthermia cart versus a malignant hyperthermia cart readily available within the hospital versus an initial dantrolene dose of 250 mg, on every maternity unit in the United States. A decision-tree model was used to estimate the expected number of lives saved, and this benefit was compared against the expected costs of the policy.We found that maintaining a malignant hyperthermia cart in every maternity unit in the United States would reduce morbidity and mortality costs by $3,304,641 per year nationally but would cost $5,927,040 annually. Sensitivity analyses showed that our results were largely driven by the extremely low incidence of general anesthesia. If cesarean delivery rates in the United States remained at 32% of all births, the general anesthetic rate would have to be greater than 11% to achieve cost benefit. The only cost-effective strategy is to keep a 250-mg dose of dantrolene on the unit for starting therapy.It is not of cost benefit to maintain a fully stocked malignant hyperthermia cart with a full supply of dantrolene within 10 min of maternity units. We recommend that hospitals institute alternative strategies (e.g., maintain a small supply of dantrolene on the maternity unit for starting treatment).

Abstract

Noninvasive cerebral optical spectrometry is a promising candidate technology for the objective assessment physiological changes during pain perception. This study's primary objective was to test if there was a significant correlation between the changes in physiological parameters as measured by a cerebral optical spectrometry-based algorithm (real-time objective pain assessment [ROPA]) and subjective pain ratings obtained from volunteers and laboring women. Secondary aims were performance assessment using linear regression and receiver operating curve (ROC) analysis.Prospective cohort study performed in Human Pain Laboratory and Labor and Delivery Unit. After institutional review board approval, we evaluated ROPA in volunteers undergoing the cold pressor test and in laboring women before and after epidural or combined spinal epidural placement. Linear regression was performed to measure correlations. ROCs and corresponding areas under the ROCs (AUC), as well as Youden's indices, as a measure of diagnostic effectiveness, were calculated.Correlations between numeric rating scale or visual analog scale and ROPA were significant for both volunteers and laboring women. AUCs for both volunteers and laboring women with numeric rating scale and visual analog scale subjective pain ratings as ground truth revealed at least good (AUC: 70%-79%) to excellent (AUC >90%) distinction between clinically meaningful pain severity differentiations (no/mild-moderate-severe).Cerebral Optical Spectrometry-based ROPA significantly correlated with subjectively reported pain in volunteers and laboring women, and could be a useful monitor for clinical circumstances where direct assessment is not available, or to complement patient-reported pain scores.

Abstract

The majority of parturients in the United States first return for evaluation by their obstetric practitioner 6 weeks after delivery. As such, there is little granular data on the pain experience, analgesic requirements, and functional recovery during the postpartum period. This prospective observational study was performed to evaluate these factors to provide expectations for patients.A total of 213 nulliparous women were enrolled and assessed daily until they completed 3 outcomes: (1) pain resolution; (2) opioid cessation; and (3) self-assessed functional recovery from delivery. The primary endpoint, pain- and opioid-free functional recovery, was the time required to reach all three of the endpoints. Pain burden was assessed as the area under the curve created by plotting the daily numerical pain rating scale against the days required to attain pain resolution. Times to attain study endpoints after cesarean delivery and vaginal delivery were compared using survival analysis.After vaginal delivery, days required for pain and opioid-free functional recovery (median [interquartile range (IQR)]) were 19 [11 to 26], for opioid cessation 0 [0 to 2], termination of all analgesic (including nonsteroidal antiinflammatories and acetaminophen) 11 [5 to 17], and pain resolution 14 [7 to 24]. Achievement of these endpoints after cesarean delivery required 27 [19 to 40], 9 [5 to 12], 16 [11 to 24], and 21 [14 to 27] days, respectively.There is clinically significant variability between healthy nulliparous parturients in the pain experience, opioid use, and functional recovery after childbirth following vaginal and cesarean delivery. Recovery to predelivery function is similar after vaginal and cesarean delivery, and approximately half of the variance was explained by pain burden.

Abstract

The aim of the study was to identify the optimal therapeutic maternal magnesium drug exposure and maternal serum concentration to prevent cerebral palsy in the extremely preterm fetus. We applied a previously constructed pharmacokinetic model adjusted for indication to a large cohort of pregnant women receiving magnesium sulfate to prevent cerebral palsy in their preterm offspring at 20 different US academic centers between December 1997 and May 2004. We simulated the population-based individual maternal serum magnesium concentration at the time of delivery and the total magnesium dose for each woman who received magnesium sulfate to determine the relationship between maternal serum magnesium level at the time of delivery and the development of cerebral palsy. Among 1905 women who met inclusion criteria, the incidence of cerebral palsy in the cohort was 3.6% for women who had received magnesium sulfate and 6.4% for controls. The simulated maternal serum concentration at delivery associated with the lowest probability of delivering an infant with cerebral palsy was 4.1 mg/dL (95%CI 3.7 to 4.4). Our population-based estimates of magnesium disposition suggest that to optimize fetal neuroprotection and prevent cerebral palsy, magnesium sulfate administration should target a maternal serum magnesium level between 3.7 and 4.4 mg/dL at delivery.

Abstract

The study aim was to investigate internet use for obtaining information about epidurals for labor and delivery.Google Trends for US data was queried from 2004 to 2015 to find the most common searches and determine temporal trends. The Google Trends query used the term [epidural] and evaluated changes in search trends over time. Search comparisons were made for each year from 2004 to 2015, and three equal time epochs during the study period (2004-07, 2008-11, 2012-15) were compared. We also compared searches for epidurals with commonly searched birth-related terms.Internet searches are increasing; there were 726000 searches for [epidural] in 2015. Search terms with the most significant growth in the past 4years (2012-15) were "birth with epidural," "pain after epidural," "labor without epidural," "epidural birth video," and "epidural vs natural". Searches for epidural side effects, risks, and pain on insertion were among the most common and were increasing most rapidly. Searches related to epidurals were more common than searches related to "natural births", "home births", and "labor pain", but were less common than searches for "midwives" or "doulas".The findings provide an insight into internet use by those seeking information about labor analgesic options. Identifying the most common and rapidly increasing online search queries may guide physician-parturient interactions and online content creation, to address labor analgesic topics that most interest users.

Abstract

The study aimed to determine whether a patient's choice for their intrathecal morphine (ITM) dose reflects their opioid requirements and pain after caesarean delivery and if giving women a choice of ITM dose would reduce opioid use and improve pain scores compared with women who did not have a choice.A total of 120 women undergoing caesarean delivery with spinal anaesthesia were enrolled in this randomized, double-blind study. Patients were randomly assigned to a choice of 100 or 200??g ITM or no choice. The study involved deception, such that all participants were still randomly assigned 100 or 200??g ITM regardless of choice. Rescue opioid use over the 48-h study period was the primary outcome measure. Pain at rest and movement and side effect (pruritus, nausea, and vomiting) data were collected 3, 6, 12, 24, 36 and 48?h postoperatively. Data are presented as median [95% confidence interval (CI)].Women who requested the larger ITM dose required more supplemental opioid [median 0.8 (95% CI 0.4-1.3)] mg morphine equivalents at each assessment interval; P ?0.001] and reported more pain with movement [median 1.2 (95% CI 0.5-1.9)] verbal numerical rating score of 0-10 points] than patients who requested the smaller ITM dose ( P ?=?0.0008), regardless of the ITM dose given. There was no difference in opioid use whether the patient was offered a perceived choice or not.Women who were given a choice and chose the larger ITM dose correctly anticipated a greater postoperative opioid requirement and more pain compared with women who chose the smaller dose. Simply being offered a choice did not impact opioid use or pain scores after caesarean delivery.ClinicalTrials.gov (NCT01425762).

Abstract

Limited understanding of risk factors exists for postpartum hemorrhage (PPH) post-vaginal delivery. The aim of this study was to identify risk factors for PPH post-vaginal delivery within a contemporary obstetric cohort.Retrospective case-control study. PPH was classified by an estimated blood loss ?500?ml. Risk factors for PPH were identified using univariable and multivariable logistic regression. We secondarily investigated maternal outcomes and medical and surgical interventions for PPH management.The study cohort comprised 159 cases and 318 controls. Compared with a second-stage duration <2?h, a second stage?3?h was associated with PPH (adjusted odds ratio=2.3; 95% CI=1.2 to 4.6). No other clinical or obstetric variables were identified as independent risk factors for PPH. Among cases, 4% received red blood cells and 1% required intensive care admission.Although PPH-related morbidity may be uncommon after vaginal delivery, PPH should be anticipated for women after a second stage ?3?h.

Abstract

Identifying pregnant women with sepsis is challenging because diagnostic clinical and laboratory criteria overlap with normal pregnant physiologic indices. Our primary study aim was to describe clinical and laboratory characteristics of women diagnosed with sepsis, severe sepsis and septic shock. Our secondary aim was to determine positive predictive values for International Classification of Disease (ICD)-9 billing codes for sepsis, severe sepsis, and septic shock.After gaining Institutional Review Board approval, we identified women with ICD-9 codes for sepsis, severe sepsis and septic shock who were admitted to a single tertiary obstetric center from 2007-2013. Diagnoses were confirmed using criteria from the International Sepsis Definitions Conference report. Demographic, obstetric, vital signs and laboratory data were abstracted by medical chart review.We identified 190 women with sepsis-related ICD-9 codes: of these, 35 (18%) women met the criteria for a clinical diagnosis of sepsis, severe sepsis or septic shock. Twenty (57%) women had a sepsis-related diagnosis after cesarean delivery. Twenty-one (60%) women had one or more pre-existing medical conditions and 19 (54%) women had one or more obstetric-related conditions. The genital tract was the most common site of infection. We observed considerable heterogeneity in maternal vital signs and laboratory indices for women with ICD-9 codes for sepsis, severe sepsis, and septic shock. The positive predictive value for each sepsis-related ICD-9 code was low: 16% (95% CI 10 to 24%) for sepsis, 10% (95% CI 3 to 25%) for severe sepsis and 24% (95% CI 10 to 46%) for septic shock.We identified marked heterogeneity in patient characteristics, clinical features, laboratory indices and microbiological findings among cohorts of women diagnosed with maternal sepsis, severe sepsis or septic shock. Based on our findings, the incidence of maternal sepsis using ICD-9 codes may be significantly overestimated.

Abstract

Venous thromboembolism is recognized as a leading cause of maternal death in the United States. Thromboprophylaxis has been highlighted as a key preventive measure to reduce venous thromboembolism-related maternal deaths. However, the expanded use of thromboprophylaxis in obstetrics will have a major impact on the use and timing of neuraxial analgesia and anesthesia for women undergoing vaginal or cesarean delivery and other obstetric surgeries. Experts from the Society of Obstetric Anesthesia and Perinatology, the American Society of Regional Anesthesia, and hematology have collaborated to develop this comprehensive, pregnancy-specific consensus statement on neuraxial procedures in obstetric patients receiving thromboprophylaxis or higher dose anticoagulants. To date, none of the existing anesthesia societies' recommendations have weighed the potential risks of neuraxial procedures in the presence of thromboprophylaxis, with the competing risks of general anesthesia with a potentially difficult airway, or maternal or fetal harm from avoidance or delayed neuraxial anesthesia. Furthermore, existing guidelines have not integrated the pharmacokinetics and pharmacodynamics of anticoagulants in the obstetric population.The goal of this consensus statement is to provide a practical guide of how to appropriately identify, prepare, and manage pregnant women receiving thromboprophylaxis or higher dose anticoagulants during the ante-, intra-, and postpartum periods. The tactics to facilitate multidisciplinary communication, evidence-based pharmacokinetic and spinal epidural hematoma data, and Decision Aids should help inform risk-benefit discussions with patients and facilitate shared decision making.

Abstract

We examined the characteristics of women who choose nitrous oxide for labor analgesia and identified factors that predict conversion from nitrous oxide to labor neuraxial analgesia.Retrospective descriptive study.Labor and Delivery Ward.146 pregnant women who used nitrous oxide for analgesia during labor and delivery between September 2014 and September 2015.Chart review only.Demographic, obstetric, and intrapartum characteristics of women using nitrous oxide were examined. Multivariable logistic regression was performed to identify factors associated with conversion from nitrous oxide to neuraxial analgesia. Data are presented as n (%), median [IQR], adjusted relative risk (aRR), and 95% confidence intervals (CI) as appropriate.During the study period, 146 women used nitrous oxide for labor analgesia (accounting for 3% of the total deliveries). The majority (71.9%) of women who used nitrous oxide were nulliparous, and over half (51.9%) had expressed an initial preference for "nonmedical birth." The conversion rate to neuraxial blockade was 63.2%, compared to a concurrent institutional rate of 85.1% in women who did not use nitrous oxide. Factors associated with conversion from nitrous oxide to neuraxial blockade were labor induction (aRR=2.0, CI 1.2-3.3) and labor augmentation (aRR=1.7, CI 1.0-2.9).Only a small number of women opted to use nitrous oxide during labor, analgesia was minimal, and most converted to neuraxial analgesia. Women with induced and augmented labors should be counseled about the increased likelihood that they will convert to neuraxial analgesia.

Abstract

We describe a case of intrathecal migration of a wire-reinforced epidural catheter in a parturient who received epidural labor analgesia. Epidural analgesia was initiated with a combined-spinal epidural technique and maintained by programmed intermittent epidural boluses. Epidural catheter aspiration after insertion was negative for cerebrospinal fluid. The patient's response to the first four doses of local anesthetic was consistent with epidural drug delivery. After the fifth dose, she developed a complete lower extremity motor block, hypotension, and high sensory blockade. Catheter aspiration was then positive for cerebrospinal fluid. After symptom resolution, labor pain was successfully managed with this inadvertent intrathecal catheter.

Abstract

Visualization of the catheter during ultrasound-guided continuous nerve block performance may be difficult but is an essential skill for regional anesthesiologists. The objective of this in vitro study was to evaluate 2 newer catheters designed for enhanced echogenicity and compare them to a widely used catheter not purposely designed for ultrasound guidance. Outcomes were the numbers of first-place rankings among all 3 catheters and scores on individual echogenicity criteria as assessed by 2 blinded reviewers. Catheters designed for echogenicity are not superior to an older regional anesthesia catheter, and results suggest that catheter preference for ultrasound-guided placement may be subjective.

Abstract

Objective ?Rectus muscle reapproximation at cesarean delivery (CD) is performed frequently by some obstetricians; however, the effect on postoperative pain is unclear. To this end, we investigated whether rectus muscle reapproximation increases postoperative pain. Materials and Methods ?This is a prospective, double-blind, randomized controlled trial of women undergoing primary CD with singleton or twin pregnancy at >35 weeks' gestation. Women were randomized to rectus muscle reapproximation with three interrupted sutures or no reapproximation. Exclusion criteria were prior cesarean, prior laparotomy, vertical skin incision, active labor, chronic analgesia use, allergy to opioid or nonsteroidal anti-inflammatory drugs, and body mass index???40. Intra- and postoperative pain management was standardized within the study protocol. The primary outcome was a combined movement pain and opioid use score averaged over the 72-hour study period, called the Silverman integrated assessment. Movement pain scores were assessed at 24, 48, and 72 postoperative hours. Results ?In total, 63 women were randomized, of whom 35 underwent rectus muscle reapproximation and 28 did not. Demographic and obstetric variables were similar between groups. Silverman integrated assessment scores during the 72-hour postoperative period were higher in the rectus muscle reapproximation group (15?±?100% vs. -31?±?78% difference from the mean; p ?=?0.04). Operative times were similar between groups (63?±?15 vs. 65?±?15 minutes; p ?=?0.61), and there were no surgical complications in either group. Maternal satisfaction with analgesia at 72 hours was high in both groups (85% [73-90] rectus muscle reapproximation vs. 90% [75-100]; p ?=?0.16). Conclusion ?Rectus muscle reapproximation increased immediate postoperative pain without differences in operative time, surgical complications, or maternal satisfaction. Benefits of rectus muscle reapproximation should be weighed against increased postoperative pain, and analgesia should be planned accordingly.

Abstract

Venous thromboembolism remains a major source of morbidity and mortality in obstetrics with an incidence of 29.8/100,000 vaginal delivery hospitalizations; cesarean delivery confers a 4-fold increased risk of thromboembolism when compared with vaginal delivery. Revised national guidelines now stipulate that the majority of women delivering via cesarean and women at risk for ante- or postpartum venous thromboembolism receive mechanical or pharmacological thromboprophylaxis. This practice change has important implications for obstetric anesthesiologists concerned about the risk of spinal epidural hematoma (SEH) among anticoagulated women receiving neuraxial anesthesia. We conducted a systematic review of published English language studies (1952-2016) and of the US Anesthesia Closed Claims Project Database (1990-2013) to identify cases of SEH associated with neuraxial anesthesia and thromboprophylaxis. We also report on SEH in obstetric patients receiving thromboprophylaxis and neuraxial anesthesia without adherence to the American Society of Regional Anesthesia (ASRA) recommendations. In our review, we initially identified 736 publications of which 10 met inclusion criteria; these were combined with the 5 cases of SEH identified in 546 obstetric Anesthesia Closed Claims reviews. None of these publications revealed SEH associated with neuraxial anesthesia and thromboprophylaxis with unfractionated heparin or low-molecular-weight heparin in obstetric patients. Based on data from 6 reports, 28 parturients had their neuraxial blockade before the minimum ASRA recommended time interval between the last anticoagulant dose and the neuraxial procedure. Based on data from 2 reports, 52 parturients received neuraxial anesthesia without their low-molecular-weight heparin dose being discontinued during the intrapartum period. Although the very low level of evidence and high heterogeneity in these reports make it difficult to draw quantitative conclusions from this systematic review, it is encouraging that this comprehensive search did not identify a single case of SEH in an obstetric patient receiving thromboprophylaxis and neuraxial anesthesia. Analysis of large-scale registries (eg, the Anesthesia Incident Reporting System of the Anesthesia Quality Institute) with more granular clinical and pharmacological data is needed to assess the impact of these practice changes on obstetric SEH incidence. In the interim, optimal care of obstetric patients depends on multidisciplinary planning of anticoagulation dosing to facilitate neuraxial anesthesia and thoughtful weighing of the relative risks and benefits of providing versus withholding neuraxial in favor of general anesthesia.

Abstract

Postpartum anemia has been associated with postpartum morbidities, such as depression and poor cognition. However, it is unclear whether postpartum anemia is associated with reduced health-related quality of life. We performed a prospective study to examine the relations between postpartum Hb levels with postpartum health-related quality of life (HRQoL). We collected data from 60 women intending vaginal delivery and assessed HRQoL and maternal fatigue on admission and on the first postpartum day using the RAND 36-Item Short-Form Health Survey (SF-36) and the Multidimensional Fatigue Inventory (MFI), respectively. Maternal Hb levels were measured on admission and on the first postpartum day. We also assessed patients for postpartum depression using the Edinburgh Postpartum Depression Scale (EPDS). We performed unadjusted and multivariate linear regression (adjusting for maternal age, parity, mode of delivery, and race) to assess the associations between postdelivery Hb with each subscale of the SF-36 and MFI. The mean predelivery and postpartum Hb levels were 12.3 (1.2) and 10.8 (1.4) g/dl, respectively. In our unadjusted and adjusted regression analyses, we observed no statistically significant associations between postpartum Hb levels with any SF-36 or MFI subscale (P?>?0.05). Based on the EPDS, only one patient was depressed; her postpartum Hb was 11.2 g/dl. Our findings suggest that postpartum Hb levels may not influence HRQoL or fatigue. However, our findings may only apply to women without predelivery anemia, severe blood loss or moderate-to-severe anemia after delivery. Future studies are needed to determine whether postpartum Hb influences HRQoL among women with moderate or severe postpartum anemia.

Abstract

Neuraxial blockade may increase external cephalic version (ECV) success rates. This survey aimed to assess the frequency and characteristics of neuraxial blockade used to facilitate ECV.We surveyed Society for Obstetric Anesthesia and Perinatology members regarding ECV practice using a 15-item survey developed by 3 obstetric anesthesiologists and tested for face validity. The survey was e-mailed in January 2015 and again in February 2015 to the 1056 Society of Obstetric Anesthesiology and Perinatology members. We present descriptive statistics of responses.Our survey response rate was 322 of 1056 (30.5%).Neuraxial blockade was used for ECV always by 18 (5.6%), often by 52 (16.1%), sometimes by 98 (30.4%), rarely by 78 (24.2%), and never by 46 (14.3%) of respondents. An anesthetic sensory block target was selected by 141 (43.8%) respondents, and analgesic by 102 (31.7%) respondents. Epidural drug doses ranged widely, including sufentanil 5-25 ?g; lidocaine 1% or 2% 10-20 mL, bupivacaine 0.0625% to 0.5% 6-15 mL, and ropivacaine 0.2% 20 mL. Intrathecal bupivacaine was used by 182 (56.5%) respondents; the most frequent doses were 2.5 mg used by 24 (7.5%), 7.5 mg used by 35 (10.9%), and 12 mg used by 30 (9.3%).Neuraxial blockade is not universally offered to facilitate ECV, and there is wide variability in neuraxial blockade techniques, in drugs and doses administered, and in the sensory blockade (anesthetic or analgesic) targeted. Future studies need to evaluate and remove barriers to allow for more widespread use of neuraxial blockade for pain relief and to optimize ECV success rates.

Abstract

Preterm labor and infections are the leading causes of neonatal deaths worldwide. During pregnancy, immunological cross talk between the mother and her fetus is critical for the maintenance of pregnancy and the delivery of an immunocompetent neonate. A precise understanding of healthy fetomaternal immunity is the important first step to identifying dysregulated immune mechanisms driving adverse maternal or neonatal outcomes. This study combined single-cell mass cytometry of paired peripheral and umbilical cord blood samples from mothers and their neonates with a graphical approach developed for the visualization of high-dimensional data to provide a high-resolution reference map of the cellular composition and functional organization of the healthy fetal and maternal immune systems at birth. The approach enabled mapping of known phenotypical and functional characteristics of fetal immunity (including the functional hyperresponsiveness of CD4(+) and CD8(+) T cells and the global blunting of innate immune responses). It also allowed discovery of new properties that distinguish the fetal and maternal immune systems. For example, examination of paired samples revealed differences in endogenous signaling tone that are unique to a mother and her offspring, including increased ERK1/2, MAPK-activated protein kinase 2, rpS6, and CREB phosphorylation in fetal Tbet(+)CD4(+) T cells, CD8(+) T cells, B cells, and CD56(lo)CD16(+) NK cells and decreased ERK1/2, MAPK-activated protein kinase 2, and STAT1 phosphorylation in fetal intermediate and nonclassical monocytes. This highly interactive functional map of healthy fetomaternal immunity builds the core reference for a growing data repository that will allow inferring deviations from normal associated with adverse maternal and neonatal outcomes.

Abstract

Programmed intermittent epidural bolus (PIEB) is an exciting new technology that has the potential to improve the maintenance of epidural labor analgesia. PIEB compared with a continuous epidural infusion (CEI) has the potential advantage of greater spread within the epidural space and therefore better sensory blockade. Studies have demonstrated a local anesthetic-sparing effect, fewer instrumental vaginal deliveries, less motor blockade, and improvements in maternal satisfaction with PIEB compared with CEI. However, the optimal PIEB regimen and pump settings remain unknown, and there are a number of logistical issues and practical considerations that should be considered when implementing PIEB. The PIEB bolus size and interval, PIEB start time delay period, and patient-controlled epidural analgesia bolus size and lockout time can influence the efficacy of PIEB used for epidural labor analgesia. Educating all members of the health care team is critical to the success of the technique. This review summarizes the role of PIEB for the maintenance of labor analgesia, outlines implementation strategies, suggests optimal settings, and presents potential limitations of the technique.

Abstract

Identifying pregnant women with sepsis is challenging because diagnostic clinical and laboratory criteria overlap with normal pregnant physiologic indices. Our primary study aim was to describe clinical and laboratory characteristics of women diagnosed with sepsis, severe sepsis and septic shock. Our secondary aim was to determine positive predictive values for International Classification of Disease (ICD)-9 billing codes for sepsis, severe sepsis, and septic shock.After gaining Institutional Review Board approval, we identified women with ICD-9 codes for sepsis, severe sepsis and septic shock who were admitted to a single tertiary obstetric center from 2007-2013. Diagnoses were confirmed using criteria from the International Sepsis Definitions Conference report. Demographic, obstetric, vital signs and laboratory data were abstracted by medical chart review.We identified 190 women with sepsis-related ICD-9 codes: of these, 35 (18%) women met the criteria for a clinical diagnosis of sepsis, severe sepsis or septic shock. Twenty (57%) women had a sepsis-related diagnosis after cesarean delivery. Twenty-one (60%) women had one or more pre-existing medical conditions and 19 (54%) women had one or more obstetric-related conditions. The genital tract was the most common site of infection. We observed considerable heterogeneity in maternal vital signs and laboratory indices for women with ICD-9 codes for sepsis, severe sepsis, and septic shock. The positive predictive value for each sepsis-related ICD-9 code was low: 16% (95% CI 10 to 24%) for sepsis, 10% (95% CI 3 to 25%) for severe sepsis and 24% (95% CI 10 to 46%) for septic shock.We identified marked heterogeneity in patient characteristics, clinical features, laboratory indices and microbiological findings among cohorts of women diagnosed with maternal sepsis, severe sepsis or septic shock. Based on our findings, the incidence of maternal sepsis using ICD-9 codes may be significantly overestimated.

Abstract

Magnesium sulfate is one of the most commonly prescribed intravenous medications in obstetrics. Despite its widespread use, there are limited data about magnesium pharmacokinetics, and magnesium is prescribed empirically without dose adjustment for different indications.The aim of this study was to characterize the pharmacokinetics and placental transfer of magnesium sulfate in pregnant women and to determine key covariates that impact the pharmacokinetics.This is a prospective pharmacokinetic cohort study of pregnant women who were prescribed magnesium sulfate for preeclampsia, preterm labor, or extreme prematurity. Women received a 4-g loading dose and 2 g/h maintenance dose as clinically indicated. Maternal blood samples were obtained before and at multiple time points during and after magnesium administration. Cord blood also was sampled at delivery. A population pharmacokinetic approach that used a nonlinear mixed-effects modeling was used to characterize magnesium disposition.Pharmacokinetic profiles of 111 pregnant women were analyzed. Magnesium clearance was 3.98 L/h in preeclamptic women and 5.88 L/h non-preeclamptic women. Steady-state concentration of magnesium was 7.2 mg/dL in preeclamptic women compared with 5.1 mg/dL in non-preeclamptic women. Maternal weight significantly impacted time to steady state. The ratio of the mean umbilical vein magnesium level to the mean maternal serum magnesium level at the time of delivery was 0.94 ± 0.15.The study accurately characterizes the pharmacokinetics of magnesium administered to pregnant women. Preeclamptic status and maternal weight significantly impact serum magnesium levels. This pharmacokinetic model could be applied to larger cohorts to help tailor magnesium treatment and account for these covariates.

Abstract

This article reviews our current understanding of amniotic fluid embolism (AFE), specifically the pathogenesis, treatment strategies, potential diagnostic tests and future therapeutic interventions for AFE.The incidence and case mortality of AFE varies widely because of heterogeneous diagnostic criteria and varying reporting mechanisms across the world. Amniotic fluid embolism is thought to be caused by abnormal activation of immunologic mechanisms following entry of fetal antigens into maternal circulation. Mast cell degranulation and complement activation may play a role in this anaphylactoid or systemic inflammatory response syndrome. Development of serum biomarkers and immune-histochemical staining techniques to aid diagnosis and develop treatments are under development and evaluation. Treatment of AFE is supportive and directed at treating cardiovascular, pulmonary, and coagulation derangements. Treatment for coagulopathy (fresh frozen plasma, cryoprecipitate/fibrinogen concentrate, and antifibrinolytics) should be initiated promptly. Recombinant factor VIIa may lead to increased mortality and should not routinely be used. C1 esterase inhibitors may be a potential therapeutic option.AFE is a devastating obstetric complication that requires early and aggressive intervention with optimal cardiopulmonary resuscitation, as well as hemorrhage and coagulopathy management. Biomarkers offer promise to aid the diagnosis of AFE, and immunomodulation may provide future therapeutic interventions to treat this lethal condition.

Abstract

The aim of this impact study was to compare the analgesic efficacy and side effect profile of programmed intermittent epidural boluses (PIEB)+patient-controlled epidural analgesia (PCEA) to continuous epidural infusion (CEI)+PCEA for maintenance labor analgesia after the introduction of PIEB at our institution.We conducted a retrospective analysis after replacing the background CEI with PIEB for our labor PCEA. Pre-change pump settings were CEI 12mL/h with PCEA (12mL bolus, lockout 15min); PIEB settings were a 9mL bolus every 45min with PCEA (10mL bolus, lockout 10min). We compared medical records of all women receiving epidural or combined spinal-epidural labor analgesia for vaginal delivery for two months before PIEB implementation to a two-month period of PIEB utilization following a five-month introductory familiarization period. The primary outcome was the proportion of women requiring rescue clinician boluses.Fewer patients in the PIEB group required rescue clinician boluses compared to the CEI group (12% vs. 19%, P=0.012). Time to first rescue bolus request and total bolus dose were not different. Peak (median [IQR]) pain scores were 2[0-5] with CEI and 0[0-4] with PIEB. There was no difference in instrumental delivery rates.Using PIEB compared to CEI as the background maintenance epidural analgesia method in conjunction with PCEA reduced the number of women requiring clinician rescue boluses while providing comparable labor analgesia. The findings of this clinical care impact study confirm the results of randomized controlled studies and suggest PIEB may be a preferable technique to CEI for the maintenance of labor analgesia.

Abstract

The aim of this study was to apply both IV fluid and forced-air warming to decrease perioperative hypothermia in women undergoing cesarean delivery with spinal anesthesia. The authors hypothesize that combined-modality active warming (AW) would increase maternal temperature on arrival at the postanesthesia care unit (PACU) and decrease the incidence of maternal perioperative hypothermia (<36°C) compared with no AW.Forty-six healthy women (n = 23 per group) undergoing scheduled cesarean delivery with spinal anesthesia (10-12 mg bupivacaine + 10 ?g fentanyl) were enrolled in this double-blinded, randomized controlled trial. Women were randomly assigned to receive either AW (warmed IV fluid and lower body forced-air warmer) or no warming (NW; blankets only). SpotOn Monitoring System was used to measure core temperature intraoperatively and for 1 hour postoperatively. The primary outcome measure was maternal temperature on arrival at the PACU. Secondary outcome measures included incidence of maternal perioperative hypothermia (<36°C), incidence of shivering, thermal comfort scores (0-100 scale), Apgar scores, and umbilical cord blood gas analysis.Demographic, obstetric, and surgical data were similar between study groups. The AW group (35.9°C ± 0.5°C) had a significantly higher temperature on arrival at the PACU compared with the NW group (35.5°C ± 0.5°C, P = 0.006; 95% confidence interval of mean difference, 0.1°C-0.7°C). Fourteen (64%) women in the AW group and 20 (91%) in the NW group were hypothermic during the study period (P = 0.031). Median (interquartile range) thermal comfort scores were 100 (95-100) in the AW group and 90 (70-100) in the NW group (P = 0.008). There were no significant differences in the incidence of intraoperative shivering (22% in the AW and 45% in the NW groups; P = 0.11), Apgar scores, or umbilical vein blood gas values between the study groups.Fluid combined with forced-air warming is effective in decreasing the incidence of perioperative hypothermia and improving maternal thermal comfort. However, despite multimodal AW, the majority of women became hypothermic, and shivering was not prevented. The findings suggest that combined AW for cesarean delivery with spinal anesthesia is difficult, and only modest benefit should be expected.

Abstract

Intrathecal catheter devices using a catheter-over-needle design and softer flexible material have been introduced to clinical practice with the aim of reducing some of the complications such as postdural puncture headaches and paresthesias seen with previous versions of intrathecal catheters. We present a case series of 5 cesarean deliveries using the Wiley Spinal intrathecal system (Epimed, Johnstown, New York), which was recently approved by the US Food and Drug Administration. The intrathecal catheter system consists of a flexible 23-gauge intrathecal cannula over a 27-gauge pencil-point spinal needle. The placement of the intrathecal catheter was successful in all 5 cases; however, paresthesias in 3 cases and postdural puncture headaches in 2 cases complicated the placement and use of the device. Although the unique catheter-over-needle design facilitates the use of smaller-gauge spinal needles for dural puncture and larger-gauge catheters for medication administration, this case series using the Wiley Spinal suggests that paresthesias and postdural puncture headaches may still limit its widespread utilization. Future studies are needed to determine the true incidence of complications and to determine the role of continuous spinal anesthesia in the obstetric population.

Abstract

The majority of pregnant women will be treated with a medication other than a vitamin supplement during their pregnancy. Almost half of these medications will be category C or D according to the former US Food and Drug Administration classification system, indicating a lack of human studies with animal studies suggesting adverse fetal effects (category C) or evidence of risk in humans (category D). Changes in maternal physiology alter drug bioavailability, distribution, clearance, and thus the drug half-life in often unpredictable ways. For many drugs, good pharmacokinetic and pharmacodynamic data in pregnancy and parturition are lacking. For other drugs, recent studies demonstrate major pharmacokinetic or pharmacodynamic changes that require dose adjustment in pregnancy, but current dosing guidelines do not reflect these data. In this review, we address the principles that underlie changes in pharmacology and physiology in pregnancy and provide information on drugs that anesthesiologists commonly encounter in treating pregnant patients.

Abstract

The phenomenon of pregnancy-induced analgesia has been demonstrated in animal models but less consistently in human studies. This study aimed to assess endogenous pain modulation, evaluating inhibitory and excitatory pain pathways, over the course of pregnancy and postpartum.Healthy pregnant women were approached for participation in this prospective multicenter cohort study. Conditioned pain modulation (CPM), mechanical temporal summation (mTS), and temperature that induced pain 6 out of 10 (pain-6) were assessed toward the end of each trimester of pregnancy (8-12, 18-22, and 36 weeks) and at 6 to 12 weeks postpartum. To assess how pregnancy affects CPM, mTS, and pain-6, a mixed-effects analysis of variance was performed.Thirty-three pregnant women were enrolled. Pregnancy did not significantly impact CPM (F3,39 = 0.30, P = 0.83, partial ? = 0.02), and there was no significant difference between CPM scores in the third trimester compared with postpartum. The mTS scores and pain-6 ratings were also not significantly changed by pregnancy (F3,42 = 1.20, P = 0.32, partial ? = 0.08; and F3,42 = 1.90, P = 0.14, partial ? = 0.12, respectively).This is the first study to assess CPM and mTS changes in pregnancy and postpartum. Endogenous pain modulation evaluating both inhibitory and excitatory pain pathways did not significantly change during pregnancy or postpartum. Future studies are required to determine the magnitude and clinical significance of pregnancy-induced analgesia.

Abstract

Checklists can optimize team performance during medical crises. However, there has been limited examination of checklist use during obstetric crises. In this simulation study we exposed multidisciplinary teams to checklist training to evaluate checklist use and team performance during a severe postpartum hemorrhage.Fourteen multidisciplinary teams participated in a postpartum hemorrhage simulation occurring after vaginal delivery. Before participating, each team received checklist training. The primary study outcome was whether each team used the checklist during the simulation. Secondary outcomes were the times taken to activate our institution-specific massive transfusion protocol and commence red blood cell transfusion, and whether a designated checklist reader was used.The majority of teams (12/14 (86%)) used the checklist. Red blood cell transfusion was administered by all teams. The median [IQR] times taken to activate the massive transfusion protocol and transfuse red blood cells were 5min 14s [3:23-6:43] and 14min 40s [12:56-17:28], respectively. A designated checklist reader was used by 7/12 (58%) teams that used the checklist. Among teams that used a checklist with versus without a designated reader, we observed no differences in the times to activate the massive transfusion protocol or to commence red blood cell transfusion (P>0.05).Although checklist training was effective in promoting checklist use, multidisciplinary teams varied in their scope of checklist use during a postpartum hemorrhage simulation. Future studies are required to determine whether structured checklist training can result in more standardized checklist use during a postpartum hemorrhage.

Abstract

This manuscript reviews the available literature on remifentanil patient-controlled intravenous analgesia in labor focusing on efficacy and safety. Remifentanil compares favorably to other potent systemic opioids but with fewer opioid-related neonatal effects. However, remifentanil provides modest and short-lasting labor analgesia that is consistently inferior when compared to neuraxial analgesia. The initial analgesic effect provided with remifentanil also diminishes as labor progresses. In several studies, remifentanil induced significant respiratory depressant effects in laboring women with episodes of desaturation, hypoventilation and even apnea. Given the safety concerns, we recommend that remifentanil patient-controlled intravenous analgesia should not be a routine analgesia technique during labor. In cases where neuraxial analgesia is refused or contraindicated and the use of remifentanil justified, continuous and careful monitoring is required to detect respiratory depression to provide safe care of both the pregnant woman and unborn child.

Abstract

The aim of the study was to assess knowledge of labor and delivery healthcare providers at a tertiary referral center in the management of pre-eclampsia and eclampsia.Thirteen multidisciplinary teams participated in this institutional review board-exempt study. Each group encountered the same scenario that involved a pre-eclamptic parturient who progressed to eclampsia. The participants were unaware of the scenario topic before the drill and that key interventions would be recorded and timed. Seven of 13 groups were randomized to have a cognitive aid available.Twelve of 13 groups attempted to lower the blood pressure; however, only 7 of 12 groups used the correct first-line antihypertensive medication as per the American College of Obstetricians and Gynecologists' guidelines. All groups requested and administered the correct bolus dose of magnesium (4-6 g intravenously). Only 2 of 13 groups took appropriate action to lower the blood pressure to a "safe range" before induction of general anesthesia, and 4 of the 13 anesthesiologists made drug modifications for induction of anesthesia. None of the 7 groups randomized to have a cognitive aid used it.Our results show widespread magnesium sulfate utilization; however, the use of antihypertensive medication is not universally administered in compliance with current guidelines. The importance of blood pressure management to reduce maternal morbidity and mortality in the setting of pre-eclampsia needs to be emphasized. Interestingly, availability of a cognitive aid did not ensure its utilization in this scenario. Findings suggest that for cognitive aids to be effectively used, it is essential that staff has been trained and become familiar with them before an emergent event.

Abstract

This is the first scientific statement from the American Heart Association on maternal resuscitation. This document will provide readers with up-to-date and comprehensive information, guidelines, and recommendations for all aspects of maternal resuscitation. Maternal resuscitation is an acute event that involves many subspecialties and allied health providers; this document will be relevant to all healthcare providers who are involved in resuscitation and specifically maternal resuscitation.

Abstract

Combination opioid-acetaminophen drugs are commonly used for pain management after cesarean delivery. The aim of this study was to determine if scheduled acetaminophen decreases opioid use compared to as-needed combination acetaminophen-opioid administration.We performed a retrospective chart review of women who underwent cesarean delivery before and after a clinical practice change. All patients received spinal anesthesia containing intrathecal morphine 200?g and scheduled non-steroidal anti-inflammatory drugs for 48h postoperatively. The first group (As-Needed Group, n=120) received combination oral opioid-acetaminophen analgesics as needed for breakthrough pain. The second group (Scheduled Group, n=120) received oral acetaminophen 650mg every 6h for 48h postoperatively with oral oxycodone administered as needed for breakthrough pain. The primary outcome was opioid use, measured in intravenous morphine mg equivalents, in the first 48h postoperatively.The Scheduled Group used 9.1±2.1mg (95% CI 5.0-13.2) fewer intravenous morphine equivalents than the As-Needed Group (P <0.0001) over the study period. Fewer patients in the Scheduled Group exceeded acetaminophen 3g daily compared to the As-Needed Group (P=0.008). Pain scores were similar between study groups.After cesarean delivery, scheduled acetaminophen results in decreased opioid use and more consistent acetaminophen intake compared to acetaminophen administered as needed via combination acetaminophen-opioid analgesics, without compromising analgesia.

Abstract

Cardiac arrest occurs in approximately 1:12,000 parturients. Among nonpregnant patients who have in-hospital cardiac arrest, those whose spontaneous circulation does not return within 15 to 20 minutes have a high risk of death and disability, so life support efforts are generally stopped after this period. However, among parturients, witnessed in-hospital arrest is often reversible and has a better prognosis. We describe a successful clinical outcome after maternal cardiac arrest and 55 minutes of advanced cardiac life support. This case underscores the importance of high-quality cardiopulmonary resuscitation and raises questions about the appropriate duration of resuscitation efforts in otherwise healthy young mothers with a potentially reversible cause of arrest.

Abstract

Uterine atony is a leading cause of postpartum hemorrhage (PPH). Although most cases of PPH respond to first line therapy with uterine massage and oxytocin administration, second line uterotonics including methylergonovine and carboprost are integral for the management of refractory uterine atony. Despite their ubiquitous use, it is uncertain whether the risk of hemorrhage-related morbidity differs in women exposed to methylergonovine or carboprost at Cesarean delivery (CD).We performed a secondary analysis using the Maternal-Fetal Medicine Units Network Cesarean Registry. We identified women who underwent CD and received either methylergonovine or carboprost for refractory uterine atony. The primary outcome was hemorrhage-related morbidity defined as intraoperative or postoperative red blood cells (RBC) transfusion or the need for additional surgical interventions including uterine artery ligation, hypogastric artery ligation, or peripartum hysterectomy for atony. We compared the risk of hemorrhage-related morbidity in those exposed to methylergonovine vs. carboprost. Propensity-score matching was used to account for potential confounders.The study cohort comprised 1,335 women; 870 (65.2%) women received methylergonovine and 465 (34.8%) women received carboprost. After accounting for potential confounders, the risk of hemorrhage-related morbidity was higher in the carboprost group than the methylergonovine group (RR = 1.7; 95% CI = 1.2 - 2.6).In this propensity-score matched analysis, methylergonovine was associated with reduced risk of hemorrhage-related morbidity during CD compared to carboprost. Based on these results, methylergonovine may be a more effective second line uterotonic.

Abstract

Uterine atony is a leading cause of postpartum hemorrhage (PPH). Although most cases of PPH respond to first line therapy with uterine massage and oxytocin administration, second line uterotonics including methylergonovine and carboprost are integral for the management of refractory uterine atony. Despite their ubiquitous use, it is uncertain whether the risk of hemorrhage-related morbidity differs in women exposed to methylergonovine or carboprost at Cesarean delivery (CD).We performed a secondary analysis using the Maternal-Fetal Medicine Units Network Cesarean Registry. We identified women who underwent CD and received either methylergonovine or carboprost for refractory uterine atony. The primary outcome was hemorrhage-related morbidity defined as intraoperative or postoperative red blood cells (RBC) transfusion or the need for additional surgical interventions including uterine artery ligation, hypogastric artery ligation, or peripartum hysterectomy for atony. We compared the risk of hemorrhage-related morbidity in those exposed to methylergonovine vs. carboprost. Propensity-score matching was used to account for potential confounders.The study cohort comprised 1,335 women; 870 (65.2%) women received methylergonovine and 465 (34.8%) women received carboprost. After accounting for potential confounders, the risk of hemorrhage-related morbidity was higher in the carboprost group than the methylergonovine group (RR = 1.7; 95% CI = 1.2 - 2.6).In this propensity-score matched analysis, methylergonovine was associated with reduced risk of hemorrhage-related morbidity during CD compared to carboprost. Based on these results, methylergonovine may be a more effective second line uterotonic.

Abstract

Malaria is a life-threatening infectious disease caused by the Plasmodium parasite. Increased global travel has resulted in an escalation in the number of imported cases seen in developed countries. Patients with malaria may present for surgery in both endemic and non-endemic countries. This article reviews the perioperative considerations when managing patients with malaria.A literature review of anesthesia, perioperative care, and malaria-related articles was performed using the MEDLINE(®), EMBASE?, and Web of Science databases to identify relevant articles published in English during 1945-2014. Of the 303 articles matching the search criteria, 265 were excluded based on title and abstract. Eleven of the remaining 38 articles were relevant to anesthesia/perioperative care, and 27 articles were identified as having direct relevance to critical care medicine.The majority of imported malaria cases are caused by the falciparum species, which is associated with the greatest degree of morbidity and mortality. Various organ systems may be impacted as a consequence of changes in the structure and function of parasitized erythrocytes. Preoperative assessment should focus on establishing the species of malaria, the severity of disease, assessing the degree of end-organ impairment, and initiating treatment of malaria prior to surgery. Intravenous artesunate is the treatment of choice for severe falciparum malaria. Quinine is a second-line agent but has a narrow therapeutic index and particularly hazardous side effects. Intraoperatively, attention should focus on fluid management, dynamics of cerebral blood flow, and avoidance of hypoglycemia. Postoperative care of severe cases should ideally take place in a critical care unit as there may be ongoing requirements for multi-organ support, including renal replacement therapy, ventilation, and/or inotropic support. The safety of neuraxial anesthesia has not been well studied in the setting of malaria.Malaria remains one of the most devastating infectious diseases worldwide. Multiple organ systems can be impacted as a consequence of changes in structure and function of parasitized erythrocytes. Safe perioperative management requires a sound knowledge of all these potential system effects.

Abstract

Ondansetron is the drug of choice to prevent nausea in women undergoing cesarean surgery and can be used to prevent neonatal abstinence syndrome (NAS). The pharmacokinetics of ondansetron have not been characterized in pregnant women or in newborns. A nonlinear mixed-effects modeling approach was used to analyze plasma samples obtained from 20 nonpregnant and 40 pregnant women following a single administration of 4 or 8 mg ondansetron, from umbilical cord blood at delivery, and from neonates after birth. The analysis indicates that: ondansetron disposition is not affected by pregnancy (P > 0.05), but influenced by dose (P < 0.05), and is characterized by rapid transplacental transfer and longer elimination half-life in neonates compared to their mother. A dosing regimen for prevention of NAS was designed based on the model. The regimen involves IV administration of 4 mg to the mothers shortly before cord clamping, or oral administration of 0.07 mg/kg (or equivalently 0.04 mg/kg IV) to neonates.

Abstract

Oxytocin may play a role in pain modulation. The analgesic effects of breastfeeding with its associated endogenous oxytocin release have not been well investigated. To determine the impact of breastfeeding on incisional, perineal, and cramping pain after cesarean and vaginal delivery.Institutional review board-approved prospective observational study.Labor and delivery and maternity wards.Healthy (American Society of Anesthesiology physical statuses 1 and 2) multiparous women who had cesarean (n = 40) and vaginal (n = 43) deliveries of singleton term infants and who were breastfeeding were enrolled.Women completed diaries to record incisional, perineal, or cramping pain scores 5 minutes before, during, and 5 minutes after breastfeeding.Demographic, obstetric, and neonatal variables, as well as analgesic use, were recorded.There was no difference in incisional pain before, during, and after breastfeeding in women post-cesarean delivery. Cramping pain was significantly increased during, as compared with before or after breastfeeding in both the vaginal (P < .001) and cesarean (P < .001) delivery cohorts.There was no analgesic effect on incisional pain during breastfeeding, indicating that endogenous oxytocin associated with breastfeeding may not play a significant role in postpartum cesarean wound pain modulation. Breastfeeding increased cramping pain after vaginal and cesarean delivery. The increase in cramping pain is most likely due to the breastfeeding-associated oxytocin surge increasing uterine tone.

Abstract

This commentary outlines the current drug labeling practices that potentially compromise the clinical care of pregnant women and their children. We highlight the need for drug manufacturers and lawmakers to change the status quo and consider practices and regulations that will provide much-needed guidance to clinicians on the safe administration of drugs to certain populations such as pregnant and nursing women. Current practices have de facto contributed to a situation in which evidence is inadequate for individual physicians and patients to weigh the risks and benefits of drug administration and make informed decisions for drug use during pregnancy and lactation.

Abstract

Intrathecal morphine-induced pruritus is a very common side-effect that is difficult to prevent or treat. Central and peripheral mechanisms are believed to be involved. The aim of this study was to determine if a peripherally acting, ?-opioid antagonist would reduce morphine-induced pruritus.We conducted a multicentre, randomized, blinded, placebo-controlled trial of women having elective Caesarean section under spinal anaesthesia with intrathecal morphine 100 ?g. After delivery, participants received either subcutaneous methylnatrexone bromide 12 mg (MNTX group, n=69) or saline (placebo group, n=68). Pruritus, nausea, pain, analgesic use, and side-effects were assessed at 2, 4, 8, and 24 h. The primary outcome was the severity of pruritus (0-10 score).One hundred and thirty-seven women completed the study, with five major protocol violations. There was no statistically significant difference between the MNTX and placebo groups for the median (IQR) pruritus AUC scores [24 (9-47) vs 36 (11-68), median difference 8.5, 95% confidence interval (CI) 0-20, P=0.09] or the worst pruritus score [3 (2-7) vs 5 (2-6), median difference 1, 95% CI 0-2, P=0.24]. The incidence of pruritus was 84% in the MNTX group and 88% in the placebo group (P=0.48). Analgesic and gastrointestinal outcomes did not significantly differ between the groups.A single dose of subcutaneous methylnaltrexone bromide 12 mg did not reduce the overall severity or incidence of pruritus. In this study, treatment with a peripherally acting ?-opioid antagonist was generally ineffective against intrathecal morphine-induced pruritus, but a small clinical effect cannot be excluded.Australian New Zealand Clinical Trials Registry (ACTRN12611000345987).

Abstract

Background. There is no consensus on the optimum management of failed tracheal intubation in emergency cesarean delivery performed for fetal compromise. The decision making process on whether to wake the patient or continue anesthesia with a supraglottic airway device is an underexplored area. This survey explores perceptions and experiences of obstetric anesthetists managing failed intubation. Methods. Anesthetists attending the Group of Obstetric Anaesthetists London (GOAL) Meeting in April 2014 were surveyed. Results. Ninety-three percent of anesthetists surveyed would not always wake the patient in the event of failed intubation for emergency cesarean delivery performed for fetal compromise. The median (interquartile range) of perceived acceptability of continuing anesthesia with a well-fitting supraglottic airway device, assessed using a visual analogue scale (0-100; 0 completely unacceptable; 100 completely acceptable), was 90 [22.5]. Preoperative patient consent regarding the use of a supraglottic airway device for surgery in the event of failed intubation would affect the decision making of 40% of anaesthetists surveyed. Conclusion. These results demonstrate that a significant body of anesthetists with a subspecialty interest in obstetric anesthesia in the UK would not always wake up the patient and would continue with anesthesia and surgery with a supraglottic airway device in this setting.

Abstract

Life-threatening anaphylaxis has been reported in women exposed to latex during surgery. We compared a written screening questionnaire to identify suspected latex sensitivity with a verbal inquiry used previously in a historical control group of women undergoing cesarean delivery to determine if the incidence of suspected latex anaphylaxis could be reduced.To identify suspected latex sensitivity among women undergoing elective cesarean delivery in a single-site tertiary unit, a nine-item written screening questionnaire was compared to historical use of a standard verbal inquiry "Are you allergic to medications or latex?". Women who had suspected latex sensitivity risk factors, or who had known latex allergy, underwent latex-free surgery. Women with suspected anaphylaxis during cesarean delivery were recommended to undergo allergen testing. The primary study outcome was suspected anaphylaxis incidence during the two periods: historical control January to December 2008, questionnaire March 2010 to April 2011.The questionnaire identified suspected latex sensitivity in 66 of 453 women (14.6%) who completed the questionnaire. The standard verbal inquiry group had identified 12 of 460 women (2.6%) with self-reported latex sensitivity. The incidence of suspected anaphylaxis during cesarean delivery was significantly lower during the questionnaire period when compared to historical controls (3/516, 0.6% vs. 11/460, 2.4%, P=0.015). For both groups, 13 of 14 women (92.9%) with suspected latex anaphylaxis were contactable; five of 13 (38.5%) had undergone allergen testing and all were positive for latex.Use of the written screening questionnaire was associated with fewer cases of suspected anaphylaxis during cesarean delivery compared with the historical control. Most women with suspected anaphylaxis did not perform allergy testing; however, all who did were positive for latex.

Abstract

Psychological characteristics may affect interpretation and expression of pain. In this study, we sought to determine whether validated psychological tests predict the labor pain experience.Thirty-nine women with singleton term or post-term pregnancies undergoing induction of labor and successful vaginal delivery comprised the study population for this prospective observational study. Four validated psychological questionnaires (Anxiety Sensitivity Index [ASI], Fear of Pain [FPQIII], Pain Catastrophizing Scale [PCS]), and Eysenck Personality Questionnaire-Short Scale) and 3-scaled ratings of anxiety, confidence, and analgesic expectations were completed before onset of labor. Outcome measures included time to epidural analgesia request, pain at request for epidural analgesia, area under the pain × time curve (AUC), epidural local anesthetic use per hour, and maternal satisfaction with analgesia. The relationship between psychological predictors and clinical responses was assessed using bivariate correlations and regression modeling.Labor pain AUC (R = 0.45, P = 0.006), epidural local anesthetic use (R = 0.45, P = 0.019), and time to epidural analgesia request (R = 0.36, P = 0.015) were predicted with models incorporating some of the prelabor predictors. ASI, PCS, personality traits (lying, extroversion, psychoticism), and scaled ratings of anxiety, confidence, and analgesic expectations all contributed to the regression models of the outcomes. After proper model selection, neither FPQIII nor PCS was in the final multivariate linear regression model for labor pain AUC, although ASI was still included (P = 0.022). There was no significant correlation between ASI and self-reported anxiety (r = 0.03, P = 0.91).Personality traits (psychoticism, extroversion, and lying), as well as scaled ratings of anxiety, confidence, and analgesia expectations, show some potential to predict labor pain, epidural local anesthetic use, and time to epidural analgesia request. Although ASI was included in the final model for labor pain AUC, and FPQ and PCS were not, further study is required to determine whether ASI is a better predictor than FPQ or PCS.

Abstract

Assessments of labour pain focus on pain intensity, not on duration. We aimed to assess the importance labouring women apply to pain intensity and duration before labour and post-delivery.Forty healthy women scheduled for labour induction were enrolled in this institutional review board-approved, prospective cohort study. Participants completed a pain preference questionnaire before active labour and within 24-h of delivery. The questionnaire consisted of seven stem questions that evaluated preference for pain intensity or duration. The pain preference ratio was determined by dividing the percentage of women who preferred reduced pain intensity for longer duration by that of those who preferred greater pain intensity for shorter duration (estimate of the odds). The overall hypothetical pain burden was determined by multiplying intensity by time. All questions presented the same overall hypothetical pain burden.Pain preference questionnaire scores demonstrated preference for low intensity pain for a longer duration rather than higher intensity for a shorter duration, both pre-labour (P<0.001) and post-delivery (P<0.001): the null median imputed as 3 of 6 (i.e. no preference for pain intensity over pain duration). This preference for pain duration over intensity was greater post-delivery compared with before labour (P=0.03). There was a significant correlation (r=0.83; P=0.04) between the pain preference ratio vs overall hypothetical pain burden before labour but not after delivery (r=0.28; P=0.59).In this preliminary labour assessment, women preferred lower pain intensity at the cost of longer pain duration. This suggests that pain intensity is the primary driver of hypothetical pain burden-a preference reinforced post-delivery.

Abstract

The objectives of this work were (i) to characterize the pharmacokinetics of cefazolin in pregnant women undergoing elective cesarean delivery and in their neonates; (ii) to assess cefazolin transplacental transmission; (iii) to evaluate the dosing and timing of preoperative, prophylactic administration of cefazolin to pregnant women; and (iv) to investigate the impact of maternal dosing on therapeutic duration and exposure in newborns. Twenty women received 1 g of cefazolin preoperatively. Plasma concentrations of total cefazolin were analyzed from maternal blood samples taken before, during, and after delivery; umbilical cord blood samples obtained at delivery; and neonatal blood samples collected 24 h after birth. The distribution volume of cefazolin was 9.44 liters/h. The values for pre- and postdelivery clearance were 7.18 and 4.12 liters/h, respectively. Computer simulations revealed that the probability of maintaining free cefazolin concentrations in plasma above 8 mg/liter during scheduled caesarean surgery was <50% in the cord blood when cefazolin was administered in doses of <2 g or when it was administered <1 h before delivery. Therapeutic concentrations of cefazolin persisted in neonates >5 h after birth. Cefazolin clearance increases during pregnancy, and larger doses are recommended for surgical prophylaxis in pregnant women to obtain the same antibacterial effect as in nonpregnant patients. Cefazolin has a longer half-life in neonates than in adults. Maternal administration of up to 2 g of cefazolin is effective and produces exposure within clinically approved limits in neonates.

Abstract

The objectives of this work were (i) to characterize the pharmacokinetics of cefazolin in pregnant women undergoing elective cesarean delivery and in their neonates; (ii) to assess cefazolin transplacental transmission; (iii) to evaluate the dosing and timing of preoperative, prophylactic administration of cefazolin to pregnant women; and (iv) to investigate the impact of maternal dosing on therapeutic duration and exposure in newborns. Twenty women received 1 g of cefazolin preoperatively. Plasma concentrations of total cefazolin were analyzed from maternal blood samples taken before, during, and after delivery; umbilical cord blood samples obtained at delivery; and neonatal blood samples collected 24 h after birth. The distribution volume of cefazolin was 9.44 liters/h. The values for pre- and postdelivery clearance were 7.18 and 4.12 liters/h, respectively. Computer simulations revealed that the probability of maintaining free cefazolin concentrations in plasma above 8 mg/liter during scheduled caesarean surgery was <50% in the cord blood when cefazolin was administered in doses of <2 g or when it was administered <1 h before delivery. Therapeutic concentrations of cefazolin persisted in neonates >5 h after birth. Cefazolin clearance increases during pregnancy, and larger doses are recommended for surgical prophylaxis in pregnant women to obtain the same antibacterial effect as in nonpregnant patients. Cefazolin has a longer half-life in neonates than in adults. Maternal administration of up to 2 g of cefazolin is effective and produces exposure within clinically approved limits in neonates.

Abstract

This consensus statement was commissioned in 2012 by the Board of Directors of the Society for Obstetric Anesthesia and Perinatology to improve maternal resuscitation by providing health care providers critical information (including point-of-care checklists) and operational strategies relevant to maternal cardiac arrest. The recommendations in this statement were designed to address the challenges of an actual event by emphasizing health care provider education, behavioral/communication strategies, latent systems errors, and periodic testing of performance. This statement also expands on, interprets, and discusses controversial aspects of material covered in the American Heart Association 2010 guidelines.

Abstract

Limited data exist regarding the echogenicity of perineural catheters, but visualization is crucial to ensure accurate placement and efficacy of the subsequent local anesthetic infusion. The objective of this study was to determine the comparative echogenicity of various regional anesthesia catheters. In an in vitro porcine-bovine model, we compared the echogenic qualities of 3 commercially available regional anesthesia catheters and 1 catheter under development to optimize echogenicity. Outcomes included visual echogenicity ranking, image quality, and scanning time, as assessed by 2 blinded investigators. The experimental catheter was found to be more echogenic than 2 of the 3 comparators.

Abstract

To explore the incidence of failure of continuous peripheral nerve blockade (CPNB) after upper extremity operations.Patient data regarding postoperative CPNB were retrospectively obtained from our institution's regional anesthesia database. Documented information on the first postoperative day included pain assessment ratings (numerical verbal pain scale, patient-reported breakthrough pain upon perceived return of sensation, appearance of the catheter site, complications, time of return of sensation, day of return of sensation, residual blockade, patient satisfaction with the block, and whether patient would receive the block again).A total of 207 patients received CPNB for postoperative analgesia. The failure rate on the first postoperative day for infraclavicular (133 patients) and supraclavicular (58 patients) CPNB was 19% and 26%, respectively. Interscalene CPNB (16 patients) yielded 3 incidences of failure. No significant difference was found between supraclavicular and infraclavicular block techniques. In addition, no significant differences were found between the incidences of CPNB failures with potentially more painful surgeries involving bone compared with potentially less painful soft tissue procedures.The CPNB technique used for hand surgery postoperative analgesia was associated with nontrivial failure rates. The potential of CPNB failure and resulting breakthrough pain upon recovery from the primary nerve block is important to help establish patient expectations.Therapeutic IV.

Abstract

Conditioned pain modulation (CPM) is a phenomenon that may be tested with a dynamic quantitative sensory test that assesses the inhibitory aspect of this pain modulatory network. Although CPM has been adopted as a clinical assessment tool in recent years, the stability of the measure has not been determined over long time intervals. The question of stability over time is crucial to our understanding of pain processing, and critical for the use of this tool as a clinical test. The primary objective of this study was to evaluate the stability of a CPM paradigm over time in healthy women. The secondary objective was to determine the potential influence of menstrual cycle phase on CPM. CPM was assessed 8 times in 22 healthy women during the follicular and luteal phases of 4 different cycles. The CPM effect was evidenced by a reduction in the pain rating of a test stimulus (6.3±0.2) with the introduction of a conditioning stimulus (5.0±0.3; P<0.001). The intraclass correlation coefficient for the CPM effect was modest (0.39; CI=0.23-0.59), suggesting that there is significant variation in CPM over long time intervals. CPM did not vary across phases in the menstrual cycle. Prior to the adoption of CPM as a clinical tool to predict individual risk and aid diagnosis, additional research is needed to establish the measurement properties of CPM paradigms and evaluate factors that influence CPM effects.

Abstract

The influence that different concentrations of labour epidural local anesthetic have on assisted vaginal delivery (AVD) and many obstetric outcomes and side effects is uncertain. The purpose of this meta-analysis was to determine whether local anesthetics utilized at low concentrations (LCs) during labour are associated with a decreased incidence of AVD when compared with high concentrations (HCs).We searched PubMed, Ovid EMBASE, Ovid MEDLINE, CINAHL, Scopus, clinicaltrials.gov, and Cochrane databases for randomized controlled trials of labouring patients that compared LCs (defined as ? 0.1% epidural bupivacaine or ? 0.17% ropivacaine) of epidural local anesthetic with HCs for maintenance of analgesia. The primary outcome was AVD and secondary outcomes included Cesarean delivery, duration of labour, analgesia, side effects (nausea and vomiting, motor block, hypotension, pruritus, and urinary retention), and neonatal outcomes. The odds ratios (OR) or weighted mean differences (WMD) and 95% confidence intervals (CI) were calculated using random effects modelling. An OR < 1 or a WMD < 0 favoured LCs.Eleven studies met our criteria (eight bupivacaine and three ropivacaine studies), providing 1,145 patients in the LCs group and 852 patients in the HCs group for analysis of the primary outcome. Low concentrations were associated with a reduction in the incidence of AVD (OR = 0.70; 95% CI 0.56 to 0.86; P < 0.001). There was no difference in the incidence of Cesarean delivery (OR 1.05; 95% CI 0.82 to 1.33; P = 0.7). The LCs group had less motor block (OR 3.9; 95% CI 1.59 to 9.55; P = 0.003), greater ambulation (OR 2.8; 95% CI 1.1 to 7.14; P = 0.03), less urinary retention (OR 0.42; 95% CI 0.23 to 0.73; P = 0.002), and a shorter second stage of labour (WMD -14.03; 95% CI -27.52 to -0.55; P = 0.04) compared with the HCs group. There were no differences between groups in pain scores, maternal nausea and vomiting, hypotension, fetal heart rate abnormalities, five-minute Apgar scores, and need for neonatal resuscitation. One-minute Apgar scores < 7 favoured the HCs group (OR 1.53; 95% CI 1.07 to 2.21; P = 0.02), and there was more pruritus in the LCs group (OR 3.36; 95% CI 1.00 to 11.31; P = 0.05).When compared with HCs of local anesthetics, the use of LCs for labour epidural analgesia reduces the incidence of AVD. This may be due to a reduction in the amount of local anesthetic used and the subsequent decrease in motor blockade. We therefore recommend the use of LCs of local anesthetics for epidural analgesia to optimize obstetric outcome.

Abstract

BACKGROUND:In this study, we sought to determine whether neuraxial anesthesia to facilitate external cephalic version (ECV) increased delivery costs for breech fetal presentation.METHODS:Using a computer cost model, which considers possible outcomes and probability uncertainties at the same time, we estimated total expected delivery costs for breech presentation managed by a trial of ECV with and without neuraxial anesthesia.RESULTS:From published studies, the average probability of successful ECV with neuraxial anesthesia was 60% (with individual studies ranging from 44% to 87%) compared with 38% (with individual studies ranging from 31% to 58%) without neuraxial anesthesia. The mean expected total delivery costs, including the cost of attempting/performing ECV with anesthesia, equaled $8931 (2.5th-97.5th percentile prediction interval $8541-$9252). The cost was $9207 (2.5th-97.5th percentile prediction interval $8896-$9419) if ECV was attempted/performed without anesthesia. The expected mean incremental difference between the total cost of delivery that includes ECV with anesthesia and ECV without anesthesia was $-276 (2.5th-97.5th percentile prediction interval $-720 to $112).CONCLUSION:The total cost of delivery in women with breech presentation may be decreased (up to $720) or increased (up to $112) if ECV is attempted/performed with neuraxial anesthesia compared with ECV without neuraxial anesthesia. Increased ECV success with neuraxial anesthesia and the subsequent reduction in breech cesarean delivery rate offset the costs of providing anesthesia to facilitate ECV.

Abstract

BACKGROUND:In this study, we sought to determine whether neuraxial anesthesia to facilitate external cephalic version (ECV) increased delivery costs for breech fetal presentation.METHODS:Using a computer cost model, which considers possible outcomes and probability uncertainties at the same time, we estimated total expected delivery costs for breech presentation managed by a trial of ECV with and without neuraxial anesthesia.RESULTS:From published studies, the average probability of successful ECV with neuraxial anesthesia was 60% (with individual studies ranging from 44% to 87%) compared with 38% (with individual studies ranging from 31% to 58%) without neuraxial anesthesia. The mean expected total delivery costs, including the cost of attempting/performing ECV with anesthesia, equaled $8931 (2.5th-97.5th percentile prediction interval $8541-$9252). The cost was $9207 (2.5th-97.5th percentile prediction interval $8896-$9419) if ECV was attempted/performed without anesthesia. The expected mean incremental difference between the total cost of delivery that includes ECV with anesthesia and ECV without anesthesia was $-276 (2.5th-97.5th percentile prediction interval $-720 to $112).CONCLUSION:The total cost of delivery in women with breech presentation may be decreased (up to $720) or increased (up to $112) if ECV is attempted/performed with neuraxial anesthesia compared with ECV without neuraxial anesthesia. Increased ECV success with neuraxial anesthesia and the subsequent reduction in breech cesarean delivery rate offset the costs of providing anesthesia to facilitate ECV.

Abstract

We documented time to key milestones and determined reasons for transport-related delays during simulated emergency cesarean.Prospective, observational investigation of delivery of care processes by multidisciplinary teams of obstetric providers on the labor and delivery unit at Lucile Packard Children's Hospital, Stanford, CA, USA, during 14 simulated uterine rupture scenarios. The primary outcome measure was the total time from recognition of the emergency (time zero) to that of surgical incision.The median (interquartile range) from time zero until incision was 9?min 27?s (8:55 to 10:27?min:s).In this series of emergency cesarean drills, our teams required approximately nine and a half minutes to move from the labor room to the nearby operating room (OR) and make the surgical incision. Multiple barriers to efficient transport were identified. This study demonstrates the utility of simulation to identify and correct institution-specific barriers that delay transport to the OR and initiation of emergency cesarean delivery.

Abstract

The aim of this study was to determine whether experimental pain tests (EPTs) using heat, pressure, and i.v. cannulation before induction of labour reliably predict epidural analgesic use and pain intensity during labour.Fifty healthy women with singleton, term pregnancies admitted for scheduled induction of labour comprised the study population for this prospective case-controlled study. Heat and pressure threshold, tolerance, and suprathreshold VAS pain ratings were determined using a Medoc thermal sensory analyser and Somedic pressure algometer, respectively, after admission before induction of labour. Verbal pain scores (VPS 0-10) were determined during peripheral 18 G i.v. placement. Response outcomes included time to epidural request, pain at epidural, labour pain [area under the curve (AUC) and worse score], and epidural local anaesthetic use. Bivariate analysis followed by forward-backward multiple regression modelling was performed to determine relationships between EPTs and labour pain response measures.Heat tolerance was significantly correlated with worst labour pain (r=0.33, P=0.025) and pain with i.v. cannulation was correlated with time to epidural request (r=0.33, P=0.025). Multiple linear regression analysis found that labour pain AUC could be predicted with suprathreshold heat VAS, heat tolerance, and pressure tolerance (R(2)=0.26; P=0.007). There were strong correlations among the various pre-labour QSTs.Pre-labour EPTs were not very reliable at predicting the labour pain experience. Consistent with postoperative studies, suprathreshold and tolerance tests appear more useful than the threshold for predicting labour pain responses. Pain rating during i.v. cannulation (an easy, rapid, point-of-care test) showed some utility as an EPT.

Abstract

The role of routine transversus abdominis plane (TAP) blocks at the time of surgery for Cesarean delivery analgesia is uncertain. Previous studies have shown no additional analgesic benefit in patients receiving intrathecal morphine. We present a series of three cases where TAP blocks were used for rescue analgesia in patients who had severe post-Cesarean delivery pain after a standard spinal anesthetic containing bupivacaine 12 mg, fentanyl 10 ?g, and morphine 200 ?g.All three women experienced severe incisional pain in the postanesthetic care unit (PACU) after offset of spinal anesthesia. When the pain did not subside with intravenous opioids, the women were offered either additional intravenous opioids or a TAP block. They chose the latter. Bilateral TAP blocks were performed in a sterile posterior approach under ultrasound guidance with 0.375% ropivacaine 20 mL with epinephrine 1:400,000. All three patients experienced significant pain relief that lasted 10-19 hr and allowed for a timely discharge from the PACU.These cases show that TAP blocks may play a valuable role as a rescue analgesic technique rather than as a routine preemptive block for all Cesarean delivery patients. Use of TAP blocks reduced the need for escalating intravenous opioid doses and potential maternal opioid-related side effects. Rescue TAP blocks should be considered after Cesarean delivery when intrathecal morphine does not provide adequate pain relief or for early breakthrough pain after offset of spinal anesthesia.

Abstract

IV fentanyl is used as a labor analgesic; however, few studies have reported the effects of IV fentanyl for early labor analgesia. We evaluated the analgesic response to IV fentanyl according to the combined effect of the single-nucleotide polymorphisms rs1799971 (c.118A/G, p. 40Asn/Asp) of the µ-opioid receptor gene (OPRM1) and rs4680 (c.472G/A, p.158Val/Met) of the catechol-O-methyltransferase (COMT) gene in women requesting labor analgesia.Labor analgesia was initiated with IV fentanyl 1.5 ?g/kg. The primary outcome was analgesic success, defined as Numerical Verbal Pain Scale score?10/100 15 minutes after the dose of fentanyl. Analgesic and side effect outcomes were compared according to OPRM1 and COMT genotypes.One hundred six women were enrolled and received IV fentanyl. IV analgesic success was 6% in women with the combination Asn/Asn-Met/Met (n=17) versus 20% in all other women combined (not Asn/Asn-Met/Met; P=0.30; difference=14%; 95% confidence interval [CI], -10% to 26%). IV analgesic success was 20% in women 118A/A (Asn/Asn) versus 21% for A/G and G/G of OPRM1 (P=0.82; difference=2%; 95% CI, -17% to 19%), and 10% in women 472A (Met/Met) versus 22% for A/G (Met/Val) and G/G (Val/Val) of COMT (P=0.24; difference=12%; 95% CI, -6% to 26%). Met/Met158 (n=31) versus Met/Val or Val/Val of COMT was associated with a smaller decrease in Numerical Verbal Pain Scale (24±18 vs 37±23; P=0.005; mean difference=-13; 99% CI, -25 to -1).This study was underpowered to draw firm conclusions on the influence of OPRM1 and COMT genotypes on labor analgesia with IV fentanyl. Further larger studies are needed to evaluate whether genotyping COMT alone or in combination with OPRM1 may have potentially useful clinical implications, such as not offering IV fentanyl in early labor to women who will most likely not benefit from it.

Abstract

Intrathecal morphine is highly effective for post-cesarean analgesia; however, the optimal dose is yet to be established. The aim of this study was to compare analgesia and side effects after a change in institutional practice to give 200 ?g rather than 100 ?g.We conducted a retrospective chart review of 241 patients who had an elective cesarean delivery and received either 100 or 200 ?g of intrathecal morphine. The primary outcome variables were mean and peak verbal pain scores (0-10) and analgesic use (milligram-morphine equivalents). Postoperative administration of antiemetics, antipruritics and episodes of nausea or vomiting were recorded. Data are reported as mean±SD or percentages with P<0.05 considered statistically significant.Women receiving intrathecal morphine 200 ?g had lower pain scores and opioid use compared with morphine 100 ?g. Mean verbal pain scores were 1.6±1.1 versus 2.0±1.1 (P=0.01) and peak verbal pain scores were 4.9±2.0 versus 5.6±1.8, respectively (P=0.008). The group receiving 200 ?g used less opioids in the first 24 h after surgery (44±35 versus 54±35 milligram-morphine equivalents, respectively, P=0.04) and received less intravenous opioids (18% versus 30%, P=0.02). However, women receiving intrathecal morphine 200 ?g had more nausea (mean number of episodes of nausea 1.9±1.3 versus 1.6±1.3, P=0.037) and used more antiemetics (52% versus 24%, P<0.0001).Intrathecal morphine 200 ?g provided better analgesia but with more nausea compared with morphine 100 ?g. Our results can be used to help guide intrathecal morphine dosing in cesarean delivery based on patient preference for analgesia versus side effects.

Abstract

The purpose of this study was to compare cardiopulmonary resuscitation (CPR) for simulated maternal cardiac arrest rendered during transport to the operating room with that rendered while stationary in the labor room. We hypothesized that the quality of CPR would deteriorate during transport.Twenty-six teams composed of 2 providers (obstetricians, nurses, or anesthesiologists) were randomized to perform CPR on the Laerdal Resusci Anne SkillReporter? mannequin during transport or while stationary. The primary outcome measure was the percentage of correctly delivered compressions, defined as compression rate ?100 beats per minute, correct sternal hand placement, compression depth ?1.5 inches (3.8 cm), and proper release. Secondary outcomes included interruptions in compressions, position of providers relative to the mannequin during the transport phase, and ventilation tidal volume.The median (interquartile range) percentage of correctly rendered compressions during phase II was 32% (10%-63%) in the transport group and 93% (58%-100%) in the stationary group (P = 0.002, 95% confidence interval of mean difference = 22%-58%). The median (interquartile range) compression rates were 124 (110-140) beats per minute in the transport group and 123 (115-132) beats per minute in the stationary group (P = 0.531). Interruptions in CPR were observed in 92% of transport and 7% of stationary drills (P < 0.001, 95% confidence interval of difference = 61%-92%). During transport, 18 providers kneeled next to the mannequin, 2 straddled the mannequin, and 4 ran alongside the gurney. Median (interquartile range) tidal volume was 270 (166-430) mL in the transport group and 390 (232-513) mL in the stationary group (P = 0.03).Our data confirm our hypothesis and demonstrate that transport negatively affects the overall quality of resuscitation on a mannequin during simulated maternal arrest. These findings, together with previously published data on transport-related delays when moving from the labor room to the operating room further strengthen recommendations that perimortem cesarean delivery should be performed at the site of maternal cardiac arrest.

Abstract

We performed a retrospective cohort analysis of pregnancies among women with moderate to complex congenital heart disease or pulmonary hypertension over a 12-year period, resulting in a cohort of 107 cases in 65 women. Neuraxial analgesia or anaesthesia was provided in 84%, 89% and 95% of spontaneous vaginal, operative vaginal and caesarean deliveries, respectively. The caesarean delivery rate was 43% compared to our institution average of 27% over the same period (p = 0.02), and 38% had operative vaginal deliveries compared to a 10.5% institution rate (p

Abstract

We describe a methodology by which we are able to collect and measure biochemical inflammatory and nociceptive mediators at the surgical wound site. Collecting site-specific biochemical markers is important to understand the relationship between levels in serum and surgical wound, determine any associations between mediator release, pain, analgesic use and other outcomes of interest, and evaluate the effect of systemic and peripheral drug administration on surgical wound biochemistry. This methodology has been applied to healthy women undergoing elective cesarean delivery with spinal anesthesia. We have measured wound exudate and serum mediators at the same time intervals as patient's pain scores and analgesics consumption for up to 48 hours post-cesarean delivery. Using this methodology we have been able to detect various biochemical mediators including nerve growth factor (NGF), prostaglandin E2 (PG-E2) substance P, IL-1?, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, TNF?, INF?, G-CSF, GM-CSF, MCP-1 and MIP-1?. Studies applying this human surgical wound bioassay have found no correlations between wound and serum cytokine concentrations or their time-release profile (J Pain. 2008; 9(7):650-7).(1) We also documented the utility of the technique to identify drug-mediated changes in wound cytokine content.

Abstract

We present anesthetic management using a continuous spinal anesthesia (CSA) technique in a patient with placenta increta who underwent elective Cesarean hysterectomy with massive postpartum hemorrhage.A 34-yr-old parturient (G3P2) was scheduled for Cesarean delivery and possible hysterectomy at 35(+3) weeks due to suspected placenta accreta. Her body mass index was 21 kg·m(-2) and she had a reassuring airway. Inadvertent dural puncture occurred during combined spinal-epidural (CSE) placement, and a decision was made to thread the epidural catheter and utilize a CSA technique. Following delivery of a healthy infant, morbid adherence of the placenta to the myometrium was confirmed, and a supracervical hysterectomy was performed. Eight litres of blood loss occurred postpartum requiring resuscitation with crystalloid 3,800 mL, colloid 1,500 mL, red blood cells 16 units, fresh frozen plasma 16 units, platelets 4 units, and cryoprecipitate 1 unit. The patient developed pulmonary edema requiring conversion to general anesthesia. The patient's cardiovascular status was stable throughout surgery, and her lungs were mechanically ventilated for 18 hr postoperatively in the intensive care unit. The intrathecal catheter was removed 24 hr after placement. She developed no adverse neurological sequelae and reported no postdural puncture headache. The pathology report confirmed placenta increta.A CSA technique may be a viable option in the event of inadvertent dural puncture during planned CSE or epidural placement in patients with a reassuring airway undergoing Cesarean delivery. Although a catheter-based neuraxial technique is appropriate for Cesarean hysterectomy for abnormal placentation, conversion to general anesthesia may be required in the event of massive perioperative hemorrhage and fluid resuscitation.

Abstract

We present a case of a parturient with babesiosis and Lyme disease who was scheduled for elective caesarean section. The caesarean section was performed under spinal anaesthesia, and the patient had a coronary artery dissection 4 days postoperatively. Neuraxial anaesthesia and possible mechanisms for the coronary artery dissection in a patient with babesiosis and Lyme disease are discussed.

Abstract

The ability to measure haemoglobin (Hb) real-time and non-invasively offers important clinical value in the assessment of acute changes in maternal Hb during the peripartum period. This study evaluates the Masimo Rainbow SET(®) Radical-7 Pulse CO-Oximeter in a pregnant population undergoing Caesarean section (CS).Fifty patients undergoing elective CS were enrolled in this prospective, controlled study and followed for 48 h after surgery. Non-invasive Masimo Hb (SpHb) values were compared with laboratory Hb values from venous blood samples drawn at baseline, immediately post-CS, and 24 h post-CS using the Bland-Altman plots. Longitudinal analysis of SpHb changes over time was performed using mixed-effects regression modelling.For the comparison between SpHb and laboratory Hb, SpHb displayed a significant positive bias at baseline {1.22 g dl(-1) [95% confidence interval (CI): 0.89-1.54]} and at 24 h post-CS [1.36 g dl(-1) (95% CI: 1.04-1.68)]. The bias immediately post-CS was 0.14 g dl(-1) (95% CI: -0.18 to 0.46). The limits of agreement at baseline, immediately post-CS, and at 24 h post-CS were: -0.9 and 3.33, -2.35 and 2.56, and -0.55 and 3.27 g dl(-1), respectively. The mean decrease in SpHb from baseline to 48 h post-CS was ?1 g dl(-1).The variability in bias and limits of agreements of the Rainbow SET(®) Radical-7 Pulse CO-Oximeter SpHb may limit its clinical utility for assessing Hb concentration in patients undergoing elective CS. Modifications are needed in the calibration of the device to improve accuracy and precision in an obstetric setting. The study was registered at clinicaltrials.gov (NCT01108471) before participant enrolment: URL=http://clinicaltrials.gov/ct2/show/NCT01108471?term=butwick&rank=1.

Abstract

Previous studies have demonstrated that the addition of intrathecal fentanyl to a spinal anesthetic for cesarean delivery improves intraoperative analgesia. However, intrathecal fentanyl may induce acute tolerance to opioids. The objective of this study was to investigate whether the addition of intrathecal fentanyl to spinal anesthesia with intrathecal morphine increases postoperative analgesic requirements and pain scores.In this randomized, double-blinded study, 40 women having elective cesarean delivery were enrolled. Patients received spinal anesthesia with hyperbaric bupivacaine 12 mg, morphine 200 ?g, and fentanyl 0, 5, 10 or 25 ?g. Each patient received intravenous patient-controlled analgesia morphine for 24h postoperatively. Outcome measures included postoperative morphine usage and pain scores, as well as intraoperative pain, nausea, hypotension and vasopressor use.Total morphine use over the 24-h post-spinal study period was similar among the study groups (P=0.129). Postoperative pain scores were higher in patients receiving fentanyl 5, 10 and 25 ?g compared to fentanyl 0 ?g control group (P=0.003).The study results suggest that intrathecal fentanyl may induce acute tolerance to intrathecal morphine. However, because there was no difference in postoperative analgesia requirement and the difference in pain scores was small, the clinical significance of this finding is uncertain.

Abstract

We describe a methodology by which we are able to collect and measure biochemical inflammatory and nociceptive mediators at the surgical wound site. Collecting site-specific biochemical markers is important to understand the relationship between levels in serum and surgical wound, determine any associations between mediator release, pain, analgesic use and other outcomes of interest, and evaluate the effect of systemic and peripheral drug administration on surgical wound biochemistry. This methodology has been applied to healthy women undergoing elective cesarean delivery with spinal anesthesia. We have measured wound exudate and serum mediators at the same time intervals as patient's pain scores and analgesics consumption for up to 48 hours post-cesarean delivery. Using this methodology we have been able to detect various biochemical mediators including nerve growth factor (NGF), prostaglandin E2 (PG-E2) substance P, IL-1?, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, TNF?, INF?, G-CSF, GM-CSF, MCP-1 and MIP-1?. Studies applying this human surgical wound bioassay have found no correlations between wound and serum cytokine concentrations or their time-release profile (J Pain. 2008; 9(7):650-7).(1) We also documented the utility of the technique to identify drug-mediated changes in wound cytokine content.

Abstract

To compare the labor room and operating room for perimortem cesarean delivery during simulated maternal arrests occurring outside the operating room. We hypothesized transport to the operating room for perimortem cesarean delivery would delay incision and other important resuscitation milestones.We randomized 15 teams composed of obstetricians, nurses, anesthesiologists, and neonatal staff to perform perimortem cesarean delivery in the labor room or operating room. A manikin with an abdominal model overlay was used for simulated cesarean delivery. The scenario began in the labor room with maternal cardiopulmonary arrest and fetal bradycardia. The primary outcome was time to incision. Secondary outcomes included times to important milestones, percentage of tasks completed, and type of incision.The median (interquartile range) times from time zero to incision were 4:25 (3:59-4:50) and 7:53 (7:18-8:57) minutes in the labor room and operating room groups, respectively (P=.004). Fifty-seven percent of labor room teams and 14% of operating room teams achieved delivery within 5 minutes. Contacting the neonatal team, placing the defibrillator, resuming compressions after analysis, and endotracheal intubation all occurred more rapidly in the labor room group.Perimortem cesarean delivery performed in the labor room was significantly faster than perimortem cesarean delivery performed after moving to the operating room. Delivery within 5 minutes was challenging in either location despite optimal study conditions (eg, the manikin was light and easily moved; teams knew the scenario mandated perimortem cesarean delivery and were aware of being timed). Our findings imply that perimortem cesarean delivery during actual arrest would require more than 5 minutes and should be performed in the labor room rather than relocating to the operating room.

Abstract

Tracheal intubation constitutes a routine part of anaesthetic practice both in the operating theatre as well as in the care of critically ill patients. The procedure is estimated to be performed 13-20 million times annually in the United States alone. There has been a recent renewal of interest in the morbidity associated with endotracheal tube cuff overinflation, particularly regarding the rationale and requirement for endotracheal tube cuff monitoring intra-operatively.

Abstract

The desire to decrease the number of cesarean deliveries has renewed interest in external cephalic version. The rationale for using neuraxial blockade to facilitate external cephalic version is to provide abdominal muscular relaxation and reduce patient discomfort during the procedure, so permitting successful repositioning of the fetus to a cephalic presentation. This review systematically examined the current evidence to determine the safety and efficacy of neuraxial anesthesia or analgesia when used for external cephalic version.A systematic literature review of studies that examined success rates of external cephalic version with neuraxial anesthesia was performed. Published articles written in English between 1945 and 2010 were identified using the Medline, Cochrane, EMBASE and Web of Sciences databases.Six, randomized controlled studies were identified. Neuraxial blockade significantly improved the success rate in four of these six studies. A further six non-randomized studies were identified, of which four studies with control groups found that neuraxial blockade increased the success rate of external cephalic version. Despite over 850 patients being included in the 12 studies reviewed, placental abruption was reported in only one patient with a neuraxial block, compared with two in the control groups. The incidence of non-reassuring fetal heart rate requiring cesarean delivery in the anesthesia groups was 0.44% (95% CI 0.15-1.32).Neuraxial blockade improved the likelihood of success during external cephalic version, although the dosing regimen that provides optimal conditions for successful version is unclear. Anesthetic rather than analgesic doses of local anesthetics may improve success. The findings suggest that neuraxial blockade does not compromise maternal or fetal safety during external cephalic version.

Abstract

A potential physicochemical interaction between epidural local anesthetics and extended-release epidural morphine (EREM) could negate the sustained release. In this study, we sought to determine the pharmacokinetic and drug effects of prior epidural lidocaine administration on EREM.Thirty healthy women undergoing cesarean delivery were enrolled in this randomized study. Patients received 8 mg EREM 1 hour after either a combined spinal-epidural (intrathecal bupivacaine and fentanyl 20 ?g with no epidural medication; group SE) or an epidural anesthetic (epidural 2% lidocaine with fentanyl 100 ?g; group E). Maximal concentration (Cmax), time to Cmax (Tmax), and AUC(0-last) (area under the concentration-time curve until the last plasma concentration that was below the limit of quantitation) for morphine levels were determined from a plasma sample at 0, 5, 10, 15, and 30 minutes, and 1, 4, 8, 12, 24, 36, 48, and 72 hours. Drug effects including pain, analgesic use, and side effects were measured for 72 hours after cesarean delivery.Epidural lidocaine administration (20-35 mL) 1 hour before epidural EREM administration increased the Cmax in group E (11.1 ± 4.9) compared with group SE (8.3 ± 7.1 ng/mL) (P = 0.038). There were no significant effects on Tmax and AUC(0-last) of venous morphine between the groups (P > 0.05). There was an increased incidence in vomiting, oxygen use, and hypotension in group E (patients who received lidocaine before EREM).A large dose of epidural lidocaine 1 hour before EREM administration alters the pharmacokinetics and drug effects of EREM. Clinicians must apply caution when EREM is administered even 1 hour after an epidural lidocaine "top-up" for cesarean delivery.

Abstract

A potential physicochemical interaction between epidural local anesthetics and extended-release epidural morphine (EREM) could negate the sustained release. In this study, we sought to determine the pharmacokinetic and drug effects of prior epidural lidocaine administration on EREM.Thirty healthy women undergoing cesarean delivery were enrolled in this randomized study. Patients received 8 mg EREM 1 hour after either a combined spinal-epidural (intrathecal bupivacaine and fentanyl 20 ?g with no epidural medication; group SE) or an epidural anesthetic (epidural 2% lidocaine with fentanyl 100 ?g; group E). Maximal concentration (Cmax), time to Cmax (Tmax), and AUC(0-last) (area under the concentration-time curve until the last plasma concentration that was below the limit of quantitation) for morphine levels were determined from a plasma sample at 0, 5, 10, 15, and 30 minutes, and 1, 4, 8, 12, 24, 36, 48, and 72 hours. Drug effects including pain, analgesic use, and side effects were measured for 72 hours after cesarean delivery.Epidural lidocaine administration (20-35 mL) 1 hour before epidural EREM administration increased the Cmax in group E (11.1 ± 4.9) compared with group SE (8.3 ± 7.1 ng/mL) (P = 0.038). There were no significant effects on Tmax and AUC(0-last) of venous morphine between the groups (P > 0.05). There was an increased incidence in vomiting, oxygen use, and hypotension in group E (patients who received lidocaine before EREM).A large dose of epidural lidocaine 1 hour before EREM administration alters the pharmacokinetics and drug effects of EREM. Clinicians must apply caution when EREM is administered even 1 hour after an epidural lidocaine "top-up" for cesarean delivery.

Abstract

Obstetric patients diagnosed with abnormal placentation (placenta accreta, increta or percreta) are at increased risk of major postpartum hemorrhage and cesarean hysterectomy. Obstetric anesthesiologists are primarily involved in intraoperative transfusion management in these cases. Hemoglobin assessment is invaluable for assisting transfusion decision-making during the acute period of obstetric hemorrhage. However, laboratory and point-of-care tests of hemoglobin concentration are time-dependent and intermittent, and do not provide a real-time assessment of change during the acute phase of blood loss. A new non-invasive hemoglobin monitor has been introduced recently, which provides real-time measurement of hemoglobin values (SpHb) using multi-wavelength pulse co-oximetry. We present a review of five patients with suspected abnormal placentation who received SpHb monitoring during cesarean hysterectomy at our institution. We discuss the potential clinical utility of non-invasive hemoglobin monitoring for pregnant patients at high risk of obstetric hemorrhage, and the potential role of SpHb in guiding transfusion therapy.

Abstract

The implications of the obstetric use of oxytocin for obstetric anaesthesia practice are summarised. The review focuses on recent research on the uterotonic effects of oxytocin for prophylaxis and management of uterine atony during caesarean delivery.Oxytocin remains the first-line agent in the prevention and management of uterine atony. In-vitro and in-vivo studies show that prior exposure to oxytocin induces uterine muscle oxytocin receptor desensitization. This may influence oxytocin dosing for adequate uterine tone following delivery. Oxytocin has important cardiovascular side-effects (hypotension, tachycardia and myocardial ischaemia). Recent studies suggest that the effective dose of oxytocin for prophylaxis against uterine atony during caesarean delivery is significantly lower than the 5-10 IU historically used by anaesthesiologists. Slow administration of small bolus doses of oxytocin minimises maternal haemodynamic disturbance. Continuous oxytocin infusions are recommended for maintaining uterine tone after bolus administration, although ideal infusion rates are still to be established. The efficacy of the long-acting oxytocin analogue carbetocin requires further investigation. Recommendations are presented for oxytocin dosing during caesarean delivery.Oxytocin remains the first-line uterotonic after vaginal and caesarean delivery. Recent research elucidates the therapeutic range of oxytocin during caesarean delivery, as well as receptor desensitization. Evidenced-based protocols for the prevention and treatment of uterine atony during caesarean delivery are recommended.

Abstract

Opioids such as morphine are the cornerstone of pain treatment. The challenge of measuring the concentrations of morphine and its active metabolites in order to assess human pharmacokinetics and monitor therapeutic drugs in children requires assays with high sensitivity in small blood volumes. We developed and validated a semi-automated LC-MS/MS assay for the simultaneous quantification of morphine and its active metabolites morphine 3?-glucuronide (M3G) and morphine 6?-glucuronide (M6G) in human plasma and in dried blood spots (DBS). Reconstitution in water (DBS only) and addition of a protein precipitation solution containing the internal standards were the only manual steps. Morphine and its metabolites were separated on a Kinetex 2.6-?m PFP analytical column using an acetonitrile/0.1% formic acid gradient. The analytes were detected in the positive multiple reaction mode. In plasma, the assay had the following performance characteristics: range of reliable response of 0.25-1000 ng/mL (r(2)?>?0.99) for morphine, 1-1,000 ng/mL (r(2)?>?0.99) for M3G, and 2.5-1,000 ng/mL for M6G. In DBS, the assay had a range of reliable response of 1-1,000 ng/mL (r(2)?>?0.99) for morphine and M3G, and of 2.5-1,000 ng/mL for M6G. For inter-day accuracy and precision for morphine, M3G and M6G were within 15% of the nominal values in both plasma and DBS. There was no carryover, ion suppression, or matrix interferences. The assay fulfilled all predefined acceptance criteria, and its sensitivity using DBS samples was adequate for the measurement of pediatric pharmacokinetic samples using a small blood of only 20-50 ?L.

Abstract

It has been suggested that morbidly obese parturients may require less local anesthetic for spinal anesthesia. The aim of this study was to determine the effective dose (ED(50)/ED(95)) of intrathecal bupivacaine for cesarean delivery in morbidly obese patients.Morbidly obese parturients (body mass index equal to or more than 40) undergoing elective cesarean delivery were enrolled in this double-blinded study. Forty-two patients were randomly assigned to receive intrathecal hyperbaric bupivacaine in doses of 5, 6, 7, 8, 9, 10, or 11 mg (n = 6 per group) coadministered with 200 ?g morphine and 10 ?g fentanyl. Success (induction) was defined as block height to pinprick equal to or more than T6 and success (operation) as success (induction) plus no requirement for epidural supplementation throughout surgery. The ED(50)/ED(95) values were determined using a logistic regression model.ED(50) and ED(95) (with 95% confidence intervals) for success (operation) were 9.8 (8.6-11.0) and 15.0 (10.0-20.0), respectively, and were similar to corresponding values of a nonobese population determined previously using similar methodology. We were unable to measure ED(50)/ED(95) values for success (induction) because so few blocks failed initially, even at the low-dose range. There were no differences with regard to secondary outcomes (i.e., hypotension, vasopressor use, nausea, and vomiting).Obese and nonobese patients undergoing cesarean delivery do not appear to respond differently to modest doses of intrathecal bupivacaine. This dose-response study suggests that doses of intrathecal bupivacaine less than 10 mg may not adequately ensure successful intraoperative anesthesia. Even when the initial block obtained with a low dose is satisfactory, it will not guarantee adequate anesthesia throughout surgery.

Anticoagulant and antithrombotic drugs in pregnancy: what are the anesthetic implications for labor and cesarean delivery?JOURNAL OF PERINATOLOGYButwick, A. J., Carvalho, B.2011; 31 (2): 73-84

Abstract

Neuraxial anesthetic techniques are commonly used during the peripartum period to provide effective pain relief for labor and anesthesia during cesarean delivery. Major neurologic complications are rare after neuraxial anesthesia; however, spinal hematoma is associated with catastrophic neurologic outcomes (including lower-limb paralysis). Anticoagulant and antithrombotic drugs can increase the risk of spinal hematoma after neuraxial anesthesia, and better understanding of the pharmacokinetics and pharmacodynamics of anticoagulants has led to greater appreciation for withholding anticoagulation before and after neuraxial anesthesia. A number of national anesthetic societies have produced guidelines for performing neuraxial anesthesia in patients receiving anticoagulation. However, there is limited information about anesthetic implications of anticoagulation during the peripartum period. This article will review the risks of spinal hematoma after neuraxial anesthesia in pregnant patients; current guidelines for neuraxial anesthesia for anticoagulated patients; and relevant pharmacological data of specific anticoagulant and antithrombotic drugs in pregnancy.

Abstract

Morphine is a drug commonly administered via the epidural or intrathecal route, and is regarded by many as the 'gold-standard' single-dose neuraxial opioid due to its postoperative analgesic efficacy and prolonged duration of action. However, respiratory depression is a recognized side effect of neuraxial morphine administered in the perioperative setting. We conducted an extensive review of articles published since 1945 that examine respiratory depression or failure associated with perioperative intrathecal or epidural morphine use. Respiratory depression was previously thought to result from the interaction of opioid in the cerebrospinal fluid with ventral medullary opioid receptors. More recently, the preBötzinger complex located in the medulla has been identified as the site responsible for the decrease in respiratory rate following systemic administration of opioids. Neurons in the preBötzinger complex expressing neurokinin-1 receptors are selectively inhibited by opioids, and therefore are the mediators of opioid-induced respiratory depression. Epidural, intrathecal and plasma pharmacokinetics of opioids are complex, vary between neuraxial compartments, and can even differ within the epidural space itself depending upon level of insertion. Caution should be exercised when prescribing systemic opioids (intravenous or oral) in addition to neuraxial morphine as this can compound the potential for early or delayed respiratory depression. There is a wide range of incidences for respiratory depression following neuraxial morphine in a perioperative setting. Disparity of definitions used for the diagnosis of respiratory depression in the literature precludes identification of the exact incidence of this rare event. The optimal neuraxial opioid dose is a balance between the conflicting demands of providing optimal analgesia while minimizing dose-related adverse effects. Dose-response studies show that neuraxial morphine appears to have an analgesic efficacy 'ceiling'. The optimal 'single-shot' intrathecal dose appears to be 0.075-0.15 mg and the ideal 'single-shot' epidural morphine dose is 2.5-3.75 mg. Analgesic efficacy studies have not been adequately powered to show differences in the incidence of clinically significant respiratory depression. Opioid antagonists such as naloxone to prevent or treat opioid-induced respiratory depression have a number of limitations. Researchers have recently focused on non-opioid drugs such as serotonin receptor agonists. Early evidence suggests that ampakine (?-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid [AMPA]) receptor modulators may be effective at reducing opioid-induced respiratory depression while maintaining analgesia. Sodium/proton exchanger type 3 (NHE3) inhibitors, which act centrally on respiratory pathways, also warrant further study.

Abstract

Wound healing is a multistep, complex process that involves the coordinated action of multiple cell types. Conflicting results have been obtained when conventional methods have been used to study wound biology. Therefore, we analyzed the wound response in a mouse genetic model.We analyzed inflammatory mediators produced within incisional wounds induced in 16 inbred mouse strains. Computational haplotype-based genetic analysis of inter-strain differences in the level of production of 2 chemokines in wounds was performed. An in vitro experimental analysis system was developed to investigate whether interleukin (IL)-1 could affect chemokine production by 2 different types of cells that are present within wounds.The level of 2 chemokines, keratinocyte-derived chemokine (KC) and macrophage inflammatory protein 1?, exhibited very large (75- and 463-fold, respectively) interstrain differences within wound tissue across this inbred strain panel. Genetic variation within Nalp1, an inflammasome component that regulates IL-1 production, correlated with the interstrain differences in KC and macrophage inhibitory protein 1? production. Consistent with the genetic correlation, IL-1? was shown to stimulate KC production by murine keratinocyte and fibroblast cell lines in vitro.Genetic variation within Nalp1 could contribute to interstrain differences in wound chemokine production by altering the amount of IL-1 produced.

Abstract

Recent evidence suggests that locally delivered local anesthetics may exert tissue-damaging effects such as chondrolysis after intraarticular injection. Alteration of the inflammatory response is a potential mechanism for local anesthetic-induced tissue toxicity. In this study, we tested the effects of continuous local anesthetic infiltration on the release of inflammatory and nociceptive mediators in skin wounds after cesarean delivery.Thirty-eight healthy women undergoing cesarean delivery with spinal anesthesia were enrolled in this study, and were randomized to receive subcutaneous surgical wound infiltration with bupivacaine 5 mg/mL or saline at 2 mL/h for 24 hours after cesarean delivery. Wound exudate was sampled at 1, 3, 5, 7, and 24 hours after cesarean delivery using a subcutaneous wound drain technique. Cytokines, chemokines, substance P, prostaglandin E(2), and nerve growth factor were assayed using multiplex Bio-Plex® (Bio-Rad, Hercules, CA) and enzyme-linked immunosorbent assays.Bupivacaine wound infusion resulted in a significant decrease of interleukin 10 and increase of substance P in wounds compared with saline infusion (area under the 24-hour concentration-time curve; P < 0.001). No statistically significant differences were detected for other cytokines, nerve growth factor, and prostaglandin E(2).This study demonstrates that the continuous administration of clinically used doses of bupivacaine into wounds affects the local composition of wound mediators. Observed changes in interleukin 10 are compatible with a disruption of antiinflammatory mechanisms. Whether such modulation combined with the release of the proinflammatory mediator substance P results in an overall proinflammatory wound response will require future studies of wound healing.

Abstract

In the accompanying paper, we demonstrate that genetic variation within Nalp1 could contribute to interstrain differences in wound chemokine production through altering the amount of interleukin (IL)-1 produced. We further investigate the role of IL-1 in incisional wound biology and its effect on wound chemokine production in vivo and whether this mechanism could be active in human subjects.A well-characterized murine model of incisional wounding was used to assess the in vivo role of IL-1 in wound biology. The amount of 7 different cytokines/chemokines produced within an experimentally induced skin incision on a mouse paw and the nociceptive response was analyzed in mice treated with an IL-1 inhibitor. We also investigated whether human IL-1? or IL-1? stimulated the production of chemokines by primary human keratinocytes in vitro, and whether there was a correlation between IL-1? and chemokine levels in 2 experimental human wound paradigms.Administration of an IL-1 receptor antagonist to mice decreased the nociceptive response to an incisional wound, and reduced the production of multiple inflammatory mediators, including keratinocyte-derived chemokine (KC) and macrophage inhibitory protein (MIP)-1?, within the wounds. IL-1? and IL-1? stimulated IL-8 and GRO-? (human homologues of murine keratinocyte-derived chemokine) production by primary human keratinocytes in vitro. IL-1? levels were highly correlated with IL-8 in human surgical wounds, and at cutaneous sites of human ultraviolet B-induced sunburn injury.IL-1 plays a major role in regulating inflammatory mediator production in wounds through a novel mechanism; by stimulating the production of multiple cytokines and chemokines, it impacts clinically important aspects of wound biology. These data suggest that administration of an IL-1 receptor antagonist within the perioperative period could decrease postsurgical wound pain.

Abstract

Tissue injury is associated with the local release of inflammatory and nociceptive mediators and the development of hyperalgesia. It is unclear whether interrupting neuronal signaling using regional anesthetic techniques at the time of the injury modifies local nociceptive and inflammatory processes. The aim of this study was to determine whether a peripheral nerve block at the time of tissue injury could modify the development of wound hyperalgesia and the local release of inflammatory and nociceptive mediators.Twelve healthy volunteers participated in this controlled, crossover, randomized study. A femoral nerve block or a sham block was established before inducing an experimental UVB burn on the thigh. Twenty-four hours later, the interstitial wound fluid was sampled, and mechanical and heat pain thresholds were assessed. Wound fluid concentrations of an array of cytokines, chemokines, nerve growth factor, prostaglandin E2, and substance P were determined.Skin inflammation was associated with the release of inflammatory and nociceptive mediators and resulted in significant tissue hyperalgesia (P < 0.001). However, the presence of a fully established peripheral nerve block at the time of tissue injury did not alter the development of hyperalgesia after regression of the block. Similarly, the presence of a peripheral nerve block did not modify the release of inflammatory or nociceptive mediators.These findings suggest that a preemptive, single-shot peripheral nerve block minimally affects wound hyperalgesia and inflammation. Continuous nerve block techniques may be better suited to alter nociceptive and inflammatory events in wounds beyond the duration of the block.

A practical guide to undertaking out of programme experience in the United States of America.British journal of hospital medicine Sultan, P., Qadan, M., Pushpanathan, E., Carvalho, B.2010; 71 (10): M158-9

Abstract

Previous work suggests the potential for suboptimal cardiopulmonary resuscitation (CPR) in the parturient but did not directly assess actual performance.We evaluated 18 videotaped simulations of maternal amniotic fluid embolus and resultant cardiac arrest. A checklist containing 10 current American Heart Association recommendations for advanced cardiac life support (ACLS) in obstetric patients was utilized. We evaluated which tasks were completed correctly and the time required to perform key actions.Proper compressions were delivered by our teams 56% of the time and ventilations 50% of the time. Critical interventions such as left uterine displacement and placing a firm back support prior to compressions were frequently neglected (in 44% and 22% of cases, respectively). The mean +/- SD overall composite score for the tasks was 45 +/- 12% (range, 20-60%). The neonatal team was called in a median (interquartile range) of 1:42 (0:44-2:18) minutes:seconds; 15 of 18 (83%) teams called only after the patient was completely unresponsive. Fifty percent of teams did not provide basic information to the neonatal teams as required by neonatal resuscitation provider guidelines.Multiple deficits were noted in the provision of CPR to parturients during simulated arrests, despite current ACLS certification for all participants. Current requirements for ACLS certification and training for obstetric staff may require revision.

Abstract

External cephalic version (ECV) is recommended by the American College of Obstetricians and Gynecologists to convert a breech fetus to vertex position and reduce the need for cesarean delivery. The goal of this study was to determine the incremental cost-effectiveness ratio, from society's perspective, of ECV compared to scheduled cesarean for term breech presentation.A computer-based decision model (TreeAge Pro 2008, Tree Age Software, Inc.) was developed for a hypothetical base case parturient presenting with a term singleton breech fetus with no contraindications for vaginal delivery. The model incorporated actual hospital costs (e.g., $8,023 for cesarean and $5,581 for vaginal delivery), utilities to quantify health-related quality of life, and probabilities based on analysis of published literature of successful ECV trial, spontaneous reversion, mode of delivery, and need for unanticipated emergency cesarean delivery. The primary endpoint was the incremental cost-effectiveness ratio in dollars per quality-adjusted year of life gained. A threshold of $50,000 per quality-adjusted life-years (QALY) was used to determine cost-effectiveness.The incremental cost-effectiveness of ECV, assuming a baseline 58% success rate, equaled $7,900/QALY. If the estimated probability of successful ECV is less than 32%, then ECV costs more to society and has poorer QALYs for the patient. However, as the probability of successful ECV was between 32% and 63%, ECV cost more than cesarean delivery but with greater associated QALY such that the cost-effectiveness ratio was less than $50,000/QALY. If the probability of successful ECV was greater than 63%, the computer modeling indicated that a trial of ECV is less costly and with better QALYs than a scheduled cesarean. The cost-effectiveness of a trial of ECV is most sensitive to its probability of success, and not to the probabilities of a cesarean after ECV, spontaneous reversion to breech, successful second ECV trial, or adverse outcome from emergency cesarean.From society's perspective, ECV trial is cost-effective when compared to a scheduled cesarean for breech presentation provided the probability of successful ECV is > 32%. Improved algorithms are needed to more precisely estimate the likelihood that a patient will have a successful ECV.

Survey of the Factors Associated with a Woman's Choice to Have an Epidural for Labor Analgesia.Anesthesiology research and practiceHarkins, J., Carvalho, B., Evers, A., Mehta, S., Riley, E. T.2010; 2010

Abstract

Objectives. The purpose of this study was to determine the factors associated with whether a woman received an epidural in labor and to determine the main source used to obtain information about labor epidurals. Methods. Over a one-month period, we surveyed all patients who labored, the day after their delivery. We used multiple logistic regression to identify potential predictive factors after initial univariate analysis. Results. 320 women who met enrollment criteria delivered during the study period and 94% completed the study. Of the 302 patients surveyed, 80% received an epidural for labor. Univariate analysis showed the following variables were associated with whether women received an epidural (P < .01): partner preference, prior epidural, language, education, type of insurance, age, duration, and pitocin use. Using computed multiple logistic regression only partner preference and prior epidural were associated with whether women received an epidural. Conclusion. It was not surprising that a previous epidural was predictive of a patient receiving an epidural. The strong association with partner preference and epidural use suggests this is an important factor when counseling pregnant women with regard to their decision to have a labor epidural.

Abstract

Many women undergo cesarean delivery without problems, however some experience significant pain after cesarean section. Pain is associated with negative short-term and long-term effects on the mother. Prior to women undergoing surgery, can we predict who is at risk for developing significant postoperative pain and potentially prevent or minimize its negative consequences? These are the fundamental questions that a team from the University of Washington, Stanford University, the Catholic University in Brussels, Belgium, Santa Joana Women's Hospital in Sćo Paulo, Brazil, and Rambam Medical Center in Israel is currently evaluating in an international research collaboration. The ultimate goal of this project is to provide optimal pain relief during and after cesarean section by offering individualized anesthetic care to women who appear to be more 'susceptible' to pain after surgery. A significant number of women experience moderate or severe acute post-partum pain after vaginal and cesarean deliveries. (1) Furthermore, 10-15% of women suffer chronic persistent pain after cesarean section. (2) With constant increase in cesarean rates in the US (3) and the already high rate in Brazil, this is bound to create a significant public health problem. When questioning women's fears and expectations from cesarean section, pain during and after it is their greatest concern. (4) Individual variability in severity of pain after vaginal or operative delivery is influenced by multiple factors including sensitivity to pain, psychological factors, age, and genetics. The unique birth experience leads to unpredictable requirements for analgesics, from 'none at all' to 'very high' doses of pain medication. Pain after cesarean section is an excellent model to study post-operative pain because it is performed on otherwise young and healthy women. Therefore, it is recommended to attenuate the pain during the acute phase because this may lead to chronic pain disorders. The impact of developing persistent pain is immense, since it may impair not only the ability of women to care for their child in the immediate postpartum period, but also their own well being for a long period of time. In a series of projects, an international research network is currently investigating the effect of pregnancy on pain modulation and ways to predict who will suffer acute severe pain and potentially chronic pain, by using simple pain tests and questionnaires in combination with genetic analysis. A relatively recent approach to investigate pain modulation is via the psychophysical measure of Diffuse Noxious Inhibitory Control (DNIC). This pain-modulating process is the neurophysiological basis for the well-known phenomenon of 'pain inhibits pain' from remote areas of the body. The DNIC paradigm has evolved recently into a clinical tool and simple test and has been shown to be a predictor of post-operative pain.(5) Since pregnancy is associated with decreased pain sensitivity and/or enhanced processes of pain modulation, using tests that investigate pain modulation should provide a better understanding of the pathways involved with pregnancy-induced analgesia and may help predict pain outcomes during labor and delivery. For those women delivering by cesarean section, a DNIC test performed prior to surgery along with psychosocial questionnaires and genetic tests should enable one to identify women prone to suffer severe post-cesarean pain and persistent pain. These clinical tests should allow anesthesiologists to offer not only personalized medicine to women with the promise to improve well-being and satisfaction, but also a reduction in the overall cost of perioperative and long term care due to pain and suffering. On a larger scale, these tests that explore pain modulation may become bedside screening tests to predict the development of pain disorders following surgery.

Abstract

Studies examining the effects of various analgesics and anesthetics on postoperative pain following cesarean delivery conventionally use the scheduled cesarean population. This study compares postoperative analgesic requirements and recovery profiles in women undergoing scheduled cesarean compared to unplanned cesarean delivery following labor. We postulated that unplanned cesarean deliveries may increase postoperative analgesic requirements.We conducted a retrospective chart review of 200 cesarean deliveries at Lucile Packard Children's Hospital, California. We examined the records of 100 patients who underwent scheduled cesarean delivery under spinal anesthesia (hyperbaric bupivacaine 12 mg with intrathecal fentanyl 10 microg and morphine 200 microg) and 100 patients that following a trail of labor required unplanned cesarean under epidural anesthesia (10-25 mL 2% lidocaine top-up with epidural morphine 4 mg after clamping of the umbilical cord). We recorded pain scores, analgesic consumption, time to first analgesic request, side effects, and length of hospital stay.We found no differences in postoperative pain scores and analgesic consumption between scheduled and unplanned cesarean deliveries for up to five days postoperatively. There were no differences in treatment of side effects such as nausea, vomiting, or pruritus (P>0.05).The results indicate that women experience similar pain and analgesic requirements after scheduled compared to unplanned cesarean delivery. This suggests that the non-scheduled cesarean population may be a suitable pain model to study pain management strategies; and that alterations in pain management are not necessary for the unplanned cesarean delivery population.

Abstract

Pre-loading with hetastarch decreases the incidence and severity of hypotension after spinal anesthesia for cesarean delivery. However, pharmacokinetic studies with crystalloid predict that fluid loading should be more efficacious if rapidly administered immediately after induction of spinal anesthesia. The aim of this study was to compare pre- and co-loading of hetastarch for the prevention of hypotension following spinal anesthesia for cesarean delivery.Forty-six healthy term parturients scheduled for cesarean delivery were randomized to receive 500 mL of 6% hetastarch intravenously, either slowly before spinal anesthesia (pre-loading) or as quickly as possible immediately after spinal anesthesia (co-loading). Systolic blood pressure was maintained at or above 90% of baseline with intravenous vasopressor boluses (ephedrine 5mg/mL+phenylephrine 25 microg/mL). The primary outcome was the volume of vasopressor mix required. Secondary outcomes included blood pressure and heart rate changes, time to first vasopressor use, nausea or vomiting, and neonatal outcomes (umbilical artery and vein pH, Apgar scores).The pre-loading group used 3.5+/-2 mL (mean+/-SD) of vasopressor mixture compared with 3.2+/-3 mL in the co-loading group (P=0.6). There were no differences in any important maternal hemodynamic or neonatal outcome values between the two study groups.Hetastarch co-loading is as effective as pre-loading for the prevention of hypotension after spinal anesthesia for cesarean delivery. Surgery need not be delayed to allow a predetermined pre-load to be administered before induction of spinal anesthesia.

Abstract

Patient-controlled epidural analgesia (PCEA) for labor was introduced into clinical practice 20 yr ago. The PCEA technique has been shown to have significant benefits when compared with continuous epidural infusion. We conducted a systematic review using MEDLINE and EMBASE (1988-April 1, 2008) of all randomized, controlled trials in parturients who received PCEA in labor in which one of the following comparisons were made: background infusion versus none; ropivacaine versus bupivacaine; high versus low concentrations of local anesthetics; and new strategies versus standard strategies. The outcomes of interest were maternal analgesia, satisfaction, motor block, and the incidence of unscheduled clinician interventions. A continuous background infusion improved maternal analgesia and reduced unscheduled clinician interventions. Larger bolus doses (more than 5 mL) may provide better analgesia compared with small boluses. Low concentrations of bupivacaine or ropivacaine provide excellent analgesia without significant motor block. Many strategies with PCEA can provide effective labor analgesia. High volume, dilute local anesthetic solutions with a continuous background infusion appear to be the most successful strategy. Research into new delivery strategies, such as mandatory programmed intermittent boluses and computerized feedback dosing, is ongoing.

Abstract

In a previous article in the Journal of Visualized Experiments we have demonstrated skin microdialysis techniques for the collection of tissue-specific nociceptive and inflammatory biochemicals in humans. In this article we will show pain-testing paradigms that are often used in tandem with microdialysis procedures. Combining pain tests with microdialysis provides the critical link between behavioral and biochemical data that allows identifying key biochemicals responsible for generating and propagating pain. Two models of evoking pain in inflamed skin of human study participants are shown. The first model evokes pain with aid of heat stimuli. Heat evoked pain as described here is predominantly mediated by small, non-myelinated peripheral nociceptive nerve fibers (C-fibers). The second model evokes pain via punctuated pressure stimuli. Punctuated pressure evoked pain is predominantly mediated by small, myelinated peripheral nociceptive nerve fibers (A-delta fibers). The two models are mechanistically distinct and independently examine nociceptive processing by the two major peripheral nerve fiber populations involved in pain signaling. Heat pain is evoked with aid of the TSA II, a commercially available thermo-sensory analyzer (Medoc Advanced Medical Systems, Durham, NC). Stimulus configuration and delivery is handled with aid of specific software. Thermodes vary in size and shape but in principle consist of a metal plate that can be heated or cooled at various rates and for different periods of time. Algorithms assessing heat-evoked pain are manifold. In the experiments shown here, study participants are asked to indicate at what point they start experiencing pain while the thermode in contact with skin is heated at a predetermined rate starting at a temperature that does not evoke pain. The thermode temperature at which a subject starts experiencing pain constitutes the heat pain threshold. Mechanical pain is evoked with punctuated probes. Such probes are commercially available from several manufacturers (von Frey hairs). However, the accuracy of von Frey hairs has been criticized and many investigators use custom made punctuated pressure probes. In the experiments shown here eight custom-made punctuated probes of different weights are applied in consecutive order, a procedure called up-down algorithm, to identify perceptional deflection points, i.e., a change from feeling no pain to feeling pain or vice versa. The average weight causing a perceptional deflection constitutes the mechanical pain threshold.

Abstract

The aim of this survey was to review cesarean delivery anesthetic practices. An online survey was sent to members of the Society of Obstetric Anesthesia and Perinatology (SOAP). The mode of anesthesia, preferred neuraxial local anesthetic and opioid agents, postoperative analgesic regimens, and monitoring modalities were assessed. 384 responses from 1,081 online survey requests were received (response rate = 36%). Spinal anesthesia is most commonly used for elective cesarean delivery (85% respondents), with 90% of these respondents preferring hyperbaric bupivacaine 0.75%. 79% used intrathecal fentanyl and 77% used morphine (median [range] dose 200?mcg [50-400]). 91% use respiratory rate, 61% use sedation scores, and 30% use pulse oximetry to monitor for postoperative respiratory depression after administration of neuraxial opioids. Postoperative analgesic regimens include: nonsteroidal anti-inflammatory agents, acetaminophen, oxycodone, and hydrocodone by 81%, 45%, 25%, and 27% respondents respectively. The majority of respondents use spinal anesthesia and neuraxial opioids for cesarean delivery anesthesia. There is marked variability in practices for monitoring respiratory depression postdelivery and for providing postoperative analgesia. These results may not be indicative of overall practice in the United States due to the select group of anesthesiologists surveyed and the low response rate.

Abstract

A laboring woman was accidentally given 45 microg of sufentanil intrathecally in the course of combined spinal-epidural analgesia. She experienced intense pruritus and transient swallowing difficulty without respiratory depression, but still had incomplete pain relief, with delivery and episiotomy repair requiring additional analgesia. This case highlights the importance of adding local anesthetic to intrathecal opioids to facilitate effective analgesia during the second stage of labor. The contributory systems issues and multiple factors that allowed this error to occur are examined.

Abstract

Previous studies have shown more extensive cephalad sensory blockade in women receiving combined spinal-epidural (CSE) anesthesia compared with single-shot spinal (SSS) anesthesia for elective cesarean delivery. It has been postulated that introduction of the epidural needle during CSE disturbs the negative pressure in the epidural space, resulting in relatively greater cerebrospinal fluid (CSF) pressure and increased spread of intrathecal local anesthetic. We tested the hypothesis that CSE results in more extensive cephalad sensory blockade than SSS anesthesia and that loss-of-resistance during initiation of CSE anesthesia increases CSF pressure compared with SSS.Thirty parturients scheduled for elective cesarean delivery were enrolled in this randomized, double-blind study. Patients received either SSS or CSE anesthesia with equal doses of intrathecal anesthetic (hyperbaric bupivacaine 12 mg, fentanyl 10 microg and morphine 200 microg). Before the intrathecal injection, the CSF pressure was measured with a fiberoptic pressure sensor. Maximum cephalad sensory blockade to pinprick, cold and touch was measured. The total dose of phenylephrine required to maintain baseline arterial blood pressure was also recorded.There were no significant differences in the median (interquartile range) pinprick sensory block height [T4 (T4-2) vs T3 (T4-1)] or CSF pressures [6 (4-12) vs 9 (8-12) mm Hg] between the SSS and CSE groups. There were no significant correlations between CSF pressure and block height or total dose of phenylephrine.The SSS and CSE techniques inserted in the lateral decubitus position resulted in similar extent of sensory blockade and CSF pressure. These findings suggest that altering the intrathecal dose is not necessary and that any difference in intrathecal pressure associated with initial placement of an epidural needle in the epidural space during CSE anesthesia is clinically inconsequential.

Abstract

Animal studies have documented a critical role for cytokines in cell signaling events underlying inflammation and pain associated with tissue injury. While clinical reports indicate an important role of cytokines in inflammatory pain, methodological limitations have made systematic human studies difficult. This study examined the utility of a human in vivo bioassay combining microdialysis with multiplex immunoassay techniques for measuring cytokine arrays in tissue. The first experiment measured cytokines in interstitial fluid collected from non-inflamed and experimentally inflamed skin (UVB). The effects of noxious heat on cytokine release were also assessed. The second experiment examined whether anti-hyperalgesic effects of the COX-inhibitor ibuprofen were associated with decreased tissue levels of the pro-inflammatory cytokines IL-1 beta and IL-6. In the first experiment, inflammation significantly increased IL-1 beta, IL-6, IL-8, IL-10, G-CSF, and MIP-1 beta. Noxious heat but not experimental inflammation significantly increased IL-7 and IL-13. In the second experiment, an oral dose of 400 and 800 mg ibuprofen produced similar anti-hyperalgesic effects suggesting a ceiling effect. Tissue levels of IL-1 beta and IL-6 were not affected after the 400mg dose but decreased significantly (44+/-32% and 38+/-13%) after the 800 mg dose. These results support the utility of explored method for tracking cytokines in human tissue and suggest that anti-hyperalgesic and anti-inflammatory effects of ibuprofen are at least partially dissociated. The data further suggest that high clinical doses of ibuprofen exert anti-inflammatory effects by down-regulating tissue cytokine levels. Explored human bioassay is a promising tool for studying the pathology and pharmacology of inflammatory and chronic pain conditions.

Abstract

Neuraxial opioids have contributed significantly to improved labor and postcesarean delivery analgesia. In the obstetric population, epidural and intrathecal opioids are associated with a very low risk of clinically significant respiratory depression. Although rare, respiratory depression is a serious risk; patients may die or suffer permanent brain damage as a consequence. This review discusses the mechanism and incidence, as well as the prevention, detection, and management of respiratory depression with morphine, extended-release epidural morphine, and lipophilic opioids in the labor and cesarean delivery setting.

Abstract

Twin pregnancies are associated with increased perinatal morbidity and mortality. No consensus exists whether vaginal twin delivery should take place in the labor room or operating room, or whether anesthesiologists should be present. We surveyed members of the California Society of Anesthesiologists (CSA) to review management of vaginal twin delivery, and examined anesthetic intervention retrospectively at our institution.230 CSA members were asked to complete an online survey on location of vaginal twin delivery in their institution and whether they were required to be present throughout. We then retrospectively reviewed charts of vaginal twin deliveries at our institution over a 36-month period to analyze frequency and type of anesthetic intervention.The online survey response rate was 58%; 64% of responders reported that vaginal twin deliveries were performed in the operating room and 55% that an anesthesiologist was present. There was a strong association between anesthesiologist's presence and delivery in the operating room (OR 7; 95% CI 3-20). We reviewed 81 charts of women who underwent vaginal twin delivery. The median (range) time that the anesthesiologist was present for each delivery was 60 (20-380) min. Of women undergoing vaginal twin delivery, 27% required anesthetic intervention during the second stage of labor with 6% having emergency cesarean delivery.There is a lack of consensus regarding the appropriate location for vaginal twin delivery and the role of anesthesiologists. A significant percentage of women undergoing vaginal twin delivery in our institution received anesthetic intervention in the immediate delivery period.

Abstract

The objectives of this study were to test the feasibility of measuring inflammatory and nociceptive biochemical mediators at the surgical site and to evaluate the relationship between wound and serum levels as well as determine any associations between mediator release, pain, and analgesic consumption after cesarean delivery. Twenty healthy women undergoing elective cesarean delivery with spinal anesthesia were enrolled. Wound exudate and serum mediators, pain scores, and analgesic consumption were measured at 1, 6, 24, and 48 hours after cesarean. In wound exudate, 19 of 20 mediators were reliably detected including interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, tumor necrosis factor-alpha, interferon-gamma, granulocyte colony stimulating factor (G-CSF), granulocyte-macrophage colony stimulating factor (GM-CSF), monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein 1 (MIP-1beta), nerve growth factor (NGF), prostaglandin E2 (PG-E2), and substance P. Wound PG-E2 and various cytokines peaked early, whereas NGF showed a more delayed release. There were no correlations between the concentration versus time profile of wound and serum cytokines. Analgesic consumption during the first 24 hours after surgery was negatively correlated with IL-1beta, IL-6, and G-CSF in the wound exudate. This study demonstrates the feasibility of collecting and measuring nociceptive and inflammatory mediators in surgical wounds at specific time points. The lack of significant correlations between wound and serum levels emphasizes the importance of determining site-specific release if localized pathologies are to be studied.This study demonstrates the feasibility of measuring real-time nociceptive and inflammatory mediators in surgical wounds. Our findings confirm the lack of correlation between wound and serum levels of many pro-inflammatory and anti-inflammatory cytokines and nerve growth factor.

Abstract

We describe a methodology by which we are able to collect and measure inflammatory and nociceptive biochemical mediators at the surgical wound site. Collecting site-specific biochemical markers allows us to evaluate the relationship between surgical wound and serum levels;determine any associations between mediator release, pain and analgesic consumption; and evaluate the effect of systemic and peripheral drug administration on surgical wound biochemistry.This methodology has been applied to healthy women undergoing elective cesarean delivery with spinal anesthesia. Wound exudate and serum mediators, in conjunction with pain scores and analgesics consumption were measured at 1, 6, 24, and 48 hours post-cesarean delivery.Biochemical mediators that were detected included IL-1?, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, TNF?, INF?, G-CSF, GM-CSF,MCP-1 and MIP-1?, nerve growth factor (NGF), prostaglandin E2 (PG-E2) and substance P. We found no correlations between wound and serum cytokines concentrations or time-release profiles (J Pain. 2008 Jul 9(7):650-7). This article describes and demonstrates the feasibility of collecting and assaying nociceptive and inflammatory mediators in surgical wounds at specific time points. The lack of significant correlations between serum and wound levels shows the importance of determining site-specific release if surgical wounds and localized pathologies are to be studied [corrected].

Abstract

The 2000-2002 triennial UK Report on Confidential Enquiries into Maternal Deaths concluded that over 50% of maternal deaths involved substandard care and that many could have been prevented. Catastrophic events leading to cardio-respiratory arrest may necessitate the resuscitation of pregnant women in various hospital locations. This study was designed to evaluate knowledge about resuscitation of parturients among anesthesiologists, obstetricians and emergency physicians.A 12-question survey was distributed anonymously to residents and faculty in the anesthesia (ANES), obstetrics (OB), and emergency medicine (EM) departments at Stanford University Medical Center/Lucile Packard Children's Hospital, Stanford, California. Questions were designed to elicit knowledge deficiencies in four critical areas: need for left uterine displacement (LUD), advanced cardiac life support algorithms (ACLS), physiologic changes of pregnancy (PHYS), and the recommendation to perform cesarean delivery in parturients (>20 weeks gestation) after 4-5 min of unsuccessful resuscitation for cardiac arrest (5CD).In total, 74/75 physicians (43% ANES, 37% OB, and 20% EM) completed the test. ANES scored highest in overall test scores, and in knowledge of PHYS (P<0.05). Scores for LUD and 5CD were similar among groups, but 25-40% of these questions were answered incorrectly. In the ACLS category, the EM group scored highest (93%).We conclude that knowledge of important basic concepts, including the need for LUD and the potential benefit of early cesarean delivery during cardiac arrest, is inadequate among all three specialties. All three departments should provide ACLS physician training with emphasis on the special considerations for parturients.

Abstract

This in-vivo human bioassay can be used to study human volunteers and patients. Samples are collected from pertinent tissue sites such as the skin via aseptically inserted microdialysis catheters (Dermal Dialysis, Erlangen, Germany). Illustrated in this example is the collection of interstitial fluid from experimentally inflamed skin in human volunteers. Sample collection can be combined with other experimental tests. For example, the simultaneous assessment of locally released biochemicals and subjective sensitivity to painful stimuli in experimentally inflamed skin provides the critical biochemical-behavioral link to identify biomarkers of pain and inflammation. Presented assay in the living human organism allows for mechanistic insight into tissue-specific processes underlying pain and/or inflammation. The method is also well suited to examine the effectiveness of existing or novel interventions--such as new drug candidates - targeting the treatment of painful and/or inflammatory conditions. This article will provide a detailed description on the use of microdialysis techniques for collecting interstitial fluid from experimentally inflamed skin lesion of human study subjects. Interstitial fluid samples are typically processed with aid of multiplex bead array immunoassays allowing assaying up to 100 analytes in samples as small in volume as 50 microliters.

Abstract

The Episure syringe is a unique spring-loaded loss-of-resistance (LOR) syringe with a coaxial compression spring within a Portex Pulsator LOR syringe. This syringe supplies a constant pressure while the operator is advancing the Tuohy needle.We evaluated the syringe using an artificial model of the ligamentum flavum, an anesthetized pig, and women who desired epidural analgesia for labor.The operator, using the spring-loaded syringe, was able to stop the forward movement of the needle, so that compared with a standard LOR syringe less of the needle protruded out the back of the laboratory model. Satisfactory labor analgesia in the human study and radiograph analyses in the porcine model confirmed epidural placement in all attempts.The spring-loaded syringe is a potentially useful LOR syringe that provides a reliable, objective end-point for identification of the epidural space.

Abstract

A single-dose of neuraxial morphine sulfate provides good post-Cesarean analgesia; however, its efficacy is limited to the first postoperative day. In a recent phase III study, extended-release epidural morphine (EREM) formulation provided more effective, prolonged analgesia after Cesarean delivery, compared to conventional epidural morphine. However, the study protocol did not allow for the use of nonsteroidal antiinflammatory drugs, used various postoperative analgesics, and monitoring and treatment of respiratory depression were not standardized. Our aims in this study were to compare postoperative analgesic consumption, pain scores and side effects of EREM with conventional morphine for the management of post-Cesarean pain in a setting more reflective of current obstetric practice.Seventy healthy parturients undergoing elective Cesarean delivery were enrolled in this randomized, double-blind study. Using a combined spinal epidural technique, patients received an intrathecal injection of bupivacaine 12 mg and fentanyl 10 mcg. After closure of the fascia, a single-dose of either conventional morphine 4 mg or EREM 10 mg was administered epidurally. Postoperatively, all patients received ibuprofen 600 mg orally every 6 h. Oral oxycodone and IV morphine were available for breakthrough pain. All patients received pulse oximetry and respiratory monitoring for 48 h post-Cesarean delivery.Single-dose EREM significantly improved pain scores at rest and during activity. The median (interquartile range) of supplemental opioid medication usage for 48 h post-Cesarean (in milligram-morphine equivalents) decreased from 17 (22) to 10 (17) mg with EREM compared to conventional epidural morphine (P = 0.037). Both drugs were well tolerated with no significant difference in adverse event profiles.EREM provides superior and prolonged post-Cesarean analgesia compared to conventional epidural morphine with no significant increases in adverse events.

Abstract

We present the case of a parturient with von Willebrand disease and scoliosis who required cesarean delivery. Neuraxial anesthesia was used for the patient. The indications for neuraxial anesthesia with regard to type 1 von Willebrand disease are reviewed.

Abstract

Superficial bleeding after labor epidural catheter placement is a common phenomenon. In addition to delaying securing the epidural catheter, it may loosen the adhesive catheter dressing. The primary aim of this study was to determine whether skin infiltration with epinephrine-containing rather than plain lidocaine reduces superficial bleeding after catheter placement. Secondary objectives were to determine whether adding epinephrine and/or sodium bicarbonate affected infiltration pain.After institutional review board approval and informed consent, 80 healthy women receiving epidural analgesia during labor were randomly assigned in a double-blind manner to four local anesthetic mixtures (n=20 in each group): group L: lidocaine 1.5%, group LB: lidocaine 1.5% with 8.4% sodium bicarbonate, group LE: lidocaine 1.5% with epinephrine 1:200000, and group LEB: lidocaine 1.5% with epinephrine 1:200000 and 8.4% sodium bicarbonate. Clinical endpoints included the amount of superficial bleeding at the catheter site, pain during local anesthetic infiltration and epidural catheter movement during labor.Demographic data were similar among the groups. The addition of epinephrine to lidocaine significantly reduced superficial bleeding. Solutions containing epinephrine were well tolerated and caused no cardiovascular disturbances. The addition of epinephrine did not increase pain, while bicarbonate reduced it [verbal score (scale 0-10) 3.6+/-2.2 vs. 2.6+/-1.8; P=0.04]. There were no differences in epidural catheter movement among the groups; no catheters became displaced during labor.Local infiltration of epinephrine-containing lidocaine before epidural catheter insertion reduces superficial bleeding and the addition of bicarbonate decreases pain during skin infiltration.

The effect of colloid and crystalloid preloading on thromboelastography prior to Cesarean deliveryAnnual Meeting of the Obstetric-Anaesthetists-AssociationButwick, A., Carvalho, B.SPRINGER.2007: 190?95

Abstract

Fluid preloading with colloids reduces hypotension after spinal anesthesia for Cesarean delivery more effectively than crystalloids. However, the effects of fluid preloading regimens on coagulation in pregnant patients remain unresolved. The aim of this study was to compare the effects on coagulation of fluid preloading with 6% hydroxyethyl starch (HES) and lactated Ringer's (LR) solution using thromboelastography (TEG) with kaolin-activated whole blood in healthy pregnant patients prior to spinal anesthesia for Cesarean delivery.After obtaining Ethics committee approval, 30 parturients were prospectively randomized prior to spinal anesthesia for elective Cesarean delivery to receive fluid preloading with either 1500 mL LR or 500 mL 6% HES over 30 min. Thromboelastography was performed immediately prior to and after fluid preloading. Standard TEG parameters were analyzed in terms of r time (min), k time (min), alpha angle (degrees) and maximum amplitude (mm).Group HES had statistically significant longer reaction times (r) and clot formation times (k) after fluid loading compared to baseline values (P < 0.05 respectively), although these post-fluid loading TEG parameters remained within a normal reference range. No significant differences in TEG values were seen after preloading within the LR group.Fluid preloading with 500 mL 6% HES in healthy parturients produced mild coagulation effects, as measured with TEG, prior to spinal anesthesia for Cesarean delivery. No significant effects on coagulation with TEG were observed following preloading with 1500 mL LR.

Abstract

Animal studies suggest that increased circulating estrogen and progesterone, and activation of the endorphin system cause prenancy-induced antinociceptive effects. Human studies have provided inconsistent results and have often lacked a nonpregnant control group. In this study, we compared sensitivity to experimental heat and cold pain in pregnant and nonpregnant women. Nineteen healthy nonpregnant female volunteers and 20 pregnant women at term were enrolled. Pain threshold and tolerance were examined using experimental heat-induced pain and cold pressor pain models. Subjects were evaluated pre- and 1-2 days post-delivery (pregnant), or on consecutive days (nonpregnant). Heat pain tolerance was significantly increased in the pregnant women during pre and postdelivery when compared with nonpregnant controls (50.0 +/- 1.0 vs 49.0 +/- 1.2 and 50.1 +/- 0.7 vs 49.2 +/- 1.2 degrees C; mean +/- sd). However, pain induced by the cold pressor test was endured for a similar amount of time by both study groups. Pregnancy-induced analgesic effects at term can be detected in a model of experimental heat pain. These effects persist during the first 24-48 h after delivery. Experimental heat pain is a suitable modality for further characterizing the phenomenon of pregnancy-induced analgesia in humans.

Abstract

Although nonsteroidal antiinflammatory drugs (NSAIDs) improve postoperative pain relief after cesarean delivery, they carry potential side effects (e.g., bleeding). Perioperative cyclooxygenase (COX)-2 inhibitors show similar analgesic efficacy to nonsteroidal antiinflammatory drugs in many surgical models but have not been studied after cesarean delivery. We designed this randomized double-blind study to determine the analgesic efficacy and opioid-sparing effects of valdecoxib after cesarean delivery. Healthy patients undergoing elective cesarean delivery under spinal anesthesia were randomized to receive oral valdecoxib 20 mg or placebo every 12 h for 72 h postoperatively. As a result of cyclooxygenase-2 inhibitors safety concerns that became apparent during this study, the study was terminated early after evaluating 48 patients. We found no differences in total analgesic consumption between the valdecoxib and placebo groups (121 +/- 70 versus 143 +/- 77 morphine mg-equivalents, respectively; P = 0.26). Pain at rest and during activity were similar between the groups despite adequate post hoc power to have detected a clinically significant difference. There were also no differences in IV morphine requirements, time to first analgesic request, patient satisfaction, side effects, breast-feeding success, or functional activity. Postoperative pain was generally well controlled. Adding valdecoxib after cesarean delivery under spinal anesthesia with intrathecal morphine is not supported at this time.

Abstract

Patient-controlled epidural analgesia (PCEA) offers many advantages over continuous epidural infusions for labor analgesia including fewer physician interventions, improved analgesia and satisfaction, and reduced local anesthetic doses. However, anesthesiologists have been slow to adopt this technique, first described in 1988. No previous studies have evaluated specific labor patient-controlled epidural analgesia practices in the United States. The aim of this study was to determine labor epidural and patient-controlled epidural analgesia practices among California hospitals.Following institutional review board exemption approval, an online survey was created using freeonlinesurveys.com. An anonymous survey was sent via e-mail to 230 California Society of Anesthesiologists' members chosen at random to represent their hospitals' labor analgesia practices.We received 133 replies from the 230 survey requests sent, a 58% response rate. The median labor epidural rate among the hospitals involved was 65% (range 0-95%). Overall, only 25% of California hospitals use patient-controlled epidural analgesia for analgesia in labor, with greater use among hospitals with dedicated obstetric anesthesia coverage and larger numbers of deliveries. Reasons given for not using patient-controlled epidural analgesia include cost, clinician preference, safety concerns and the inconvenience of change.Despite the potential advantages of patient-controlled epidural analgesia over continuous epidural infusions for labor analgesia, patient-controlled epidural analgesia has not been widely adopted in California hospitals. Education regarding this technique is needed to encourage its increased use.

Abstract

Obstetric hemorrhage is a leading cause of maternal mortality. We describe the anesthetic management of elective cesarean delivery in patients at high risk for hemorrhage. The utility and limitations of intraarterial balloon catheter placement and epidural anesthesia are described.

Abstract

When deciding on neuraxial medication (e.g., spinal opioids) for cesarean delivery (CS) under regional anesthesia, anesthesiologists make treatment decisions that "trade off" relieving pain with the potential for increased risk of side effects. No previous studies have examined obstetric patients' anesthesia preferences. Researchers administered 100 written surveys to pregnant women attending our institutions' expectant parent class. We determined patients' preferences for importance of specific intraoperative and postoperative anesthesia outcomes using priority ranking and relative value scales. We also explored patients' fears, concerns, and tolerance regarding CS and analgesics. Eighty-two of 100 surveys were returned and analyzed. Pain during and after CS was the greatest concern followed by vomiting, nausea, cramping, pruritus, and shivering. Ranking and relative value scores were closely correlated (R2 = 0.7). Patients would tolerate a visual analog pain score (0-100 mm) of 56 +/- 22 before exposing their baby to the potential effects of analgesics they receive. In contrast to previous general surgical population surveys that found nausea and vomiting as primary concerns, we found pain during and after CS as parturients' most important concern. Common side effects such as pruritus and shivering caused only moderate concern. This information should be used to guide anesthetic choices, e.g., inclusion of spinal opioids given in adequate doses.Medical care can be improved by incorporating patients' preferences into medical decision making. We surveyed obstetric patients to determine their preferences regarding potential cesarean delivery anesthesia outcomes. Unlike general surgical patients who rate nausea and vomiting highest, parturients considered pain during and after cesarean delivery the most important concern.

Abstract

The ideal intrathecal isobaric bupivacaine dose for cesarean delivery anesthesia is uncertain. While small doses (5-9 mg) of bupivacaine may reduce side effects such as hypotension, they potentially increase spinal anesthetic failures. This study determined the ED50 and ED95 of intrathecal isobaric bupivacaine (with adjuvant opioids) for cesarean delivery.After institutional review board approval and written informed consent were obtained, 48 parturients undergoing elective cesarean delivery under combined spinal-epidural anesthesia were enrolled in this double-blind, randomized, dose-ranging study. Patients received a 5-, 6-, 7-, 8-, 9-, 10-, 11-, or 12-mg intrathecal isobaric bupivacaine dose with 10 microg fentanyl and 200 microg morphine. Overall anesthetic success was recorded when no intraoperative epidural supplement was required during the cesarean delivery. ED50 and ED95 values for overall anesthetic success were determined using a logistic regression model.ED50 and ED95 values for overall anesthetic success were 7.25 and 13.0 mg, respectively. No advantages for low doses could be demonstrated with regard to hypotension, nausea, vomiting, pruritus, or maternal satisfaction, although this study was underpowered to detect significant differences in secondary outcome variables.The ED50 and ED95 values (7.25 and 13.0 mg, respectively) for intrathecal isobaric bupivacaine in this circumstance are similar to values the authors determined recently for hyperbaric bupivacaine using similar methodology. These ED50 and ED95 values are significantly higher than those advocated in previous reports in which success was claimed using lower intrathecal bupivacaine doses. The current study used stricter criteria to define "successful" anesthesia and support the use of larger bupivacaine doses to ensure adequate patient comfort.

Abstract

In this multicenter, randomized, controlled study, we compared the analgesic efficacy and safety profile of a new single-dose extended-release epidural morphine (EREM) formulation (DepoDur) with that of epidural morphine sulfate for the management of postoperative pain for up to 48 h after elective cesarean delivery. ASA physical status I or II parturients (n = 75) were anesthetized with a combined spinal/epidural technique. Parturients received intrathecal bupivacaine 12-15 mg and fentanyl 10 mug for spinal anesthesia and a single epidural injection of either 5 mg of standard (conventional preservative-free) morphine or 5, 10, or 15 mg of extended-release morphine after cord clamping for postoperative pain control. Single-dose EREM 10 and 15 mg groups significantly decreased total supplemental opioid medication use and improved functional ability scores for 48 h after surgery compared with those receiving 5 mg of standard morphine. Visual analog scale pain scores at rest and with activity at 24 to 48 h after dosing were significantly better in the 10- and 15-mg single-dose EREM groups versus the standard morphine group. There were no significant differences between the two 5 mg (single-dose EREM and standard morphine) groups. Single-dose EREM was well tolerated, and most adverse events were mild to moderate in severity. Single-dose EREM is a potentially beneficial epidural analgesic for the management of post-cesarean delivery pain and has particular advantages over standard morphine for the period from 24 to 48 h after surgery.

Abstract

Remifentanil is a useful adjunct in general anesthesia for high-risk obstetric patients. It provides effective blunting of the rapid hemodynamic changes that may be associated with airway manipulation and surgical stimulation. There have been no previous reports of opioid-related rigidity in the neonate delivered by a parturient receiving intraoperative remifentanil. We present a case of short-lived neonatal rigidity and respiratory depression following remifentanil administration during cesarean section to a parturient with autoimmune hepatitis complicated by cirrhosis, esophageal varices and thrombocytopenia.

Abstract

Acute normovolaemic haemodilution (ANH) is widely used as part of a blood conservation strategy to minimize the use of allogenic blood in the peri-operative period. Its role has not been proven in a prospective randomized trial. The potential benefits must not blind clinicians to the possible hazards. We report a life-threatening complication of ANH prior to induction of anaesthesia for aortic aneurysm repair.

The output of two sevoflurane vaporizers in the presence of heliumBRITISH JOURNAL OF ANAESTHESIACarvalho, B., Sanders, D.2002; 88 (5): 711-713

Abstract

Modern vaporizers are designed to deliver accurate and stable concentrations of volatile anaesthetic agents. Carrier gas composition may adversely affect the output from vaporizers. No previous study has tested helium in combination with sevoflurane vaporizers, a clinically useful combination especially in anaesthesia for upper airway obstruction.This study evaluated the effect of increasing helium concentrations, carrier gas flow rates and varying the vaporizer dial setting on the output from Blease Datum and Drager Vapor 19.3 sevoflurane vaporizers.The presence of helium in the carrier gas had negligible effects on the output from both of the sevoflurane vaporizers tested. Carrier gas flow rates had the greatest effect on output but changes were within +/- 10% of baseline.Helium/oxygen mixtures can be used with these vaporizers without adversely affecting their performance.

Abstract

A case is presented in which a relatively modest blood transfusion resulted in acute hyperkalaemia with a 'near-miss' cardiac arrest. While transfusion-related hyperkalaemia usually occurs in association with massive transfusions, several factors may have increased the risk of such an acute reaction. A high index of suspicion is required, especially in patients with risk factors. Anaesthetists should not be lulled into a false sense of security simply because modest volumes of blood are being transfused.